In this article, you can read some narrations about the day of Ghadir.

Chapter One: The place of Eid Ghadir in the religion

1- Eid of Caliphate and Wilayah

I went to Imam Sadiq (AS) and said: Do Muslims have Eid other than Eid al-Adha, Eid al-Fitr, and Friday? 
Imam (AS) said: Yes, the day when the Messenger of God (PBUH&HP) appointed the Commanders of the Faithful (to the caliphate and guardianship.

2- The best Eid of the nation

The Messenger of Allah (PBUH&HP) said:
Ghadir Day is the highest Eid of my nation and it is the day that Allah Almighty commanded. On that day, I will appoint my brother Ali ibn Abi Talib as the flag bearer (and commander) of my ummah, so that the people after him will be guided by him, and that is the day when Allah completed the religion and completed the blessings on my ummah, and He liked Islam as a religion for them.

3- The great feast of Allah

Imam Sadiq (AS) said:

The day of Ghadir is the great feast of Allah, God did not send a prophet, unless he took this day as Eid and recognized its greatness, and the name of this day in heaven is the day of the covenant and on earth, the day of the firm covenant and public presence.

4- Eid ul-Fitr

Imam Sadiq (AS) was asked: do believers have any other Eid besides Eid al-Fitr and Eid al-Adha and Friday? And he answered:
Yes, they have a bigger Eid and that is the day when the Commander of the Faithful (AS) was raised in Ghadir, and the Messenger of God placed the issue of guardianship on the shoulders of men and women.

5- Day of renewal of allegiance

Ammar bin Hariz says:

On the eighteenth day of the month of DhulHija, I arrived at the service of Imam Sadiq (AS) and found him fasting. The Imam said to me: Today is a great day, Allah has given it greatness and on that day he completed the religion of the believers and completed the blessings on them and renewed the previous covenant.

6- Heavenly Eid

Imam Reza (AS) said:

My father quoted his father (Imam Sadiq (AS)) as saying:
Ghadir Day is more famous in the sky than on earth.

7- Unique Eid

Ali (AS) said:

Today (Eid Ghadir) is a very great day.

On this day, the opening has come and the status (of those who deserved it) has risen, and the proofs of Allah have been clarified, and the position of purity has been clearly spoken, and today is the day of the completion of religion and the day of the covenant.

8- Happy Eid

Imam Sadiq (AS) said:

I swear by God, if the people knew the true virtue of "Ghadir Day", the angels would shake hands with them ten times a day, and the gifts of God to the one who knew that day cannot be counted.

9- Clarification Eid

Imam Sadiq (AS) said:

... The day of Ghadir among the days of Eid al-Fitr and Eid al-Adha and Friday is like the moon among the stars.

10- One of the four divine holidays

Imam Sadiq (AS) said:

When the Day of Judgment comes, the four days will hasten to Allah as the bride will hasten to her chamber. Those days are: Eid al-Fitr and Eid al-Adha and Friday and Ghadir.

Chapter 2: The merits and demerits of Ghadir

11- Day of message and providence

The Prophet (PBUH&HP) (on the day of Ghadir) said:

O Muslims! Let those present inform the absentees: I recommend the one who believes in me and acknowledges me to the guardianship of Ali, beware that the guardianship of Ali is my guardianship and my guardianship is the guardianship of my God. This was a covenant from my Lord which He commanded me to deliver to you.

12- Feeding day

Imam Sadiq (AS) said:

Eid Ghadir is the day when the Prophet (PBUH&HP) raised Ali (AS) as the flag bearer for the people and revealed his virtue on this day and introduced his successor, then he fasted that day in gratitude to the Almighty Allah and that day is the day of fasting, worship, feeding, and visiting religious brothers. That day is the day of gaining the pleasure of the merciful Allah and rubbing the dust of the devil's nose.

13- Gift day

Ali (AS) (in the sermon of Eid Ghadir) said:

When you reach each other, shake hands with each other and give gifts to each other on this day; whoever was there and heard these words, let him go to the poor, let the rich go to the poor, and let the strong go to the weak, prophet (PBUH&HP) commanded me so.

14- Day of sponsorship

The Commander of the Faithful (AS) said:

... How will it be for someone who is responsible for the living expenses of a number of believing men and women (on the Day of Ghadir), if I guarantee him/her to Allah that he will be safe from disbelief and poverty.

15- Thanksgiving and happiness day

Imam Sadiq (AS) said:

Eid Ghadir is a day of worship, prayer, thanksgiving, and praise to Allah, and it is a day of joy and happiness for the sake of our family, may God bless them, and I would like you to fast that day.

16- Charity Day

It was narrated from Imam Sadiq (AS) that he said:

One dirham to brothers with faith and knowledge on the day of Eid Ghadir is equal to one thousand dirhams, so give alms to your brothers on this day and make every believing man and woman happy.

17- Day of joy and happiness

Imam Sadiq (AS) said:
Ghadir is the day of Eid and joy and happiness and the day of fasting is as a thanksgiving for divine blessings.

18- Congratulations

Ali (AS) said:

Return home after the gathering (on the day of Ghadir), may Allah have mercy on you. Develop for your family, do good to your brothers, thank Allah for the blessing He has given you, unite so Allah will unite you, do good so Allah will establish your friendship, give each other Allah's blessing and congratulations, as Allah has congratulated you on this day by rewarding you many times over other Eids, such rewards will not be except on the day of Eid Ghadir.

19- Day of greetings and innocence

I said to Imam Sadiq (AS): Do Muslims have any other Eid besides those two? 
He said: Yes, the greatest and best Eid. 
I said: What day is it?
He said: The day when Amir al-Mu'minin was appointed as the flag bearer of the people.
I said: on that day, what should we do? 
He said: Fast and send greetings to Muhammad and his family and seek acquittal from the oppressors because the prophets instructed the successors to observe Eid on the day when the successor is chosen.

20- Eid al-Adha

Imam Sadiq (AS) said:

On the day of Eid-ul-Ghadir, remember Allah with fasting and worship and remembrance of the Prophet and his family, because the Messenger of Allah instructed the Commanders of the Faithful to observe Eid on that day, just as the prophets instructed their successors to observe that day as Eid. They did the same.

Resources

1.  The Holy Quran.
2. Amali Sheikh Sadough, Islamic Library.
3. QurbalAsnad Abdullah Ja'far al-Humairi, Al-Bayt.
4. Mesbah Al-Muttahid, Sheikh Tusi, Shiite Fiqh Foundation.
5. Wasael Shiah, Sheikh Har Ameli, Islamic Library.
6. Safinat al-Bahar, Sheikh Abbas Qomi, Aswa.
    

According to dictionary definitions salvation means “deliverance from the power and effects of sin” [1]. Even some people believe that all Abrahamic religions have been sent to human beings to free them from the effects of their sins and guide them to the path of salvation. However, there are some major differences in the way that followers of different Abrahamic religions believe in the concept of salvation and that the above definition is not necessarily compatible with the Islamic meaning of Salvation. Therefore, this article is a study on the concept of salvation in Islam and tries to point out its major differences with Christianity.

The Concept of Original Sin: Rational or Not?

Before starting the argument about the concept of salvation in Christianity, it is important to point out the two main ideas of Christian Catholic theologians:

1-    ‘Adam by his sin caused the fall of the human generation on earth and as a result of this worldly life, he caused death for the human generation. 

2-    Adam by his fault transmitted sin to the human generation’ [2].

According to some Christians’ opinion, death and sin are transmitted to the human race generation after generation, "for as by the disobedience of one man, many [i.e., all men] were made sinners" (Romans 5:19) [3].

Now let us study how Christianity explains the concept of salvation for men who are all born sinners.

The Concept of Salvation in Christianity 

Some Christian sects believe that all men are born sinners, and it becomes more complicated when the belief comes to the point that says “no amount of human goodness, human works, human morality, or religious activity can gain acceptance with God or get anyone into heaven; the moral man, the religious man, and the immoral and non-religious, are all in the same boat” [4].

“In the Christian doctrine of salvation, God has rescued man through Christ (John 3:17). Specifically, it was Jesus’ death on the cross and subsequent resurrection that achieved man’s salvation (Romans 5:10; Ephesians 1:7). It is explicitly stated in The Bible that salvation is the gracious, undeserved gift of God (Ephesians 2:5, 8) and is only available through faith in Jesus Christ (Acts 4:12)” [5].

The Concept of Salvation in Islam

There are a few differences between the story of Adam and Eve in the Bible and the Quran, one of which is the concept of original sin in Christianity that is contrary to the Islamic teachings. According to Islam, we are all born pure and even if we consider Adam’s act as a sin [i], it is not logical to count it as an everlasting sin for the whole human generation. According to Islam, everyone is responsible for his/her own acts: “no bearer of burden shall bear the burden of another” (6: 164).

Therefore, according to Islam, salvation is not defined as the human’s deliverance from the original sin, but it is a path that guides human beings towards spiritual development and reaching God. 

Even following the prophets in Islam, never means that the human generation can be saved by having belief in their prophethood, but it is by following their guidance and the rules of religion and by doing “righteous deeds” (7:42) that one can reach salvation: 

“And those who have faith and do righteous deeds—they shall be the inhabitants of paradise; they will remain in it [forever].” (2: 82)

In the Quran, Allah introduces prophet Muhammad (PBUH&HP) as the one who rescues people from their burdens and shackles. (7:157). We need to find out what those burdens and shackles are and how the prophet is supposed to relieve people from them, which are all mentioned in the Quran.

By finding the answer to the above question, we will realize the Islamic viewpoint on the concept of salvation and the role of Prophets and people in attaining it. 

What Are the Burdens and Shackles on the Human Shoulders?

The Quran exegetes have different interpretations of burdens and shackles that are mentioned in this Holy Book; including superstitions, wrong habits, and traditions, ignorance, discrimination, false rules of the society, oppression, and dictatorship of the government, etc. It is also said that these burdens were those hard rituals and laws that God had obliged over the Jews [6].

But the deliverance that prophet brings for people is not reachable by sacrificing himself. As it is mentioned in the Quran the duty of prophets is to invite people to the right path and teach them the book and purify them by giving them the guidelines for a successful life (24: 54). However, it is the human himself who has to choose and do righteous deeds to reach salvation. 

Therefore, according to the Quran sins cannot be transmitted from one person to another, just as a prophet cannot take away the sins of his people by sacrificing himself; “No bearer shall bear another’s burden” (17:15).

Conclusion

Salvation in Islam opens the gate of hope into people’s hearts. Unlike Christianity, in Islam people are not sinful and can reach the closest levels to God and His messengers by doing righteous deeds, acting according to the religious rules and living a decent life. And having true faith in God and his apostle is necessary but not enough. 

As mentioned in the Quran, the human is a creature that “its virtues and vices” are inspired to him and it is the human who chooses one and leaves the other behind [7]. Therefore, in the Islamic doctrine, it is the human’s free will that makes his/her destiny; “one who purifies it (the soul) is felicitous, and one who betrays it fails” (91: 9-10).

To sum up, believing in Jesus and his sacrifice for the salvation of human race is not acceptable according to Islam. But the only way of salvation is the belief in the prophets, especially the last one, Prophet Muhammad (PBUH&HP), and in the messages that he delivered to us. These messages invite us to do righteous deeds based on our conscious act and choice. And if the belief is not accompanied by righteous deeds it will not lead to salvation. 

Notes: 

[i]. Muslims believe in the infallibility of prophets. Also, the reason for which Muslims do not count Adam’s act as sin is that at his time there had been no religion and no specific frameworks for human behavior. And God had not ordered him not to eat of the forbidden tree, but He recommended Adam and Eve to keep away from that tree. Therefore, they had not committed a sin, to face punishment, rather they had chosen to take an action regarding the forbidden tree and they faced its consequences. 

References: 

1. salvation
2. original sin
3. ibid
4. https://bible.org/article/gods-plan-salvation
5. Christian salvation
6. Makarem Shirazi, N. Payam-e Ghor’an , Vol. 7, p. 25 
7. The Quran, Chapter Shams (91), Verse 18