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.
    

One of the features of a believing Muslim is that he/she always wants to grow closer to Allah and constantly seeks His satisfaction. For this reason, there are numerous narrations from the infallible Imams (A.S) indicating the right time and place for seeking closeness to Allah.It is clear that God is the Most Gracious, and his Mercy is always bestowed upon humankind wherever they are. However, there are special times and places at which God’s benevolence towards His creatures becomes even greater. One of these occasions is the Day of Arafah.

When is the Day of Arafah?

The ninth day of Dhu al-Hijjah (the final month of the Islamic lunar calendar) is the day of Arafah when Hajj pilgrims stand on the plain of Arafat (a vast desert about 20 km southeast of Mecca) to pray. Arafah can be translated as knowing, understanding or theosophy [1]. 

According to historians, it was on the plain of Arafat where Adam and Eve met each other once again after their descent from heaven and long separation upon the Earth, and their sins were forgiven by Allah.
It also recalls how Gabriel taught the prophet Abraham (AS) all the Hajj rituals on the plain of Arafat.

The day of Arafah is so important that Imam Hussain (AS), the third infallible Shia Imam, recited the famous supplication of Arafah one year during his pilgrimage to Mecca on this day.

The virtues of the Day of Arafah

Arafah is one of the most blessed days in Islam that carries a lot of merits for the ones who are present on the plain of Arafat and other people elsewhere. This day in its blessedness and sacredness weighs the same as the Night of Qadr. It has been narrated, “People who were not able to achieve their purpose in the Night of Qadr or those who were not forgiven on that day, Arafah is the last opportunity for them” [2].

So, many Muslims occupy themselves with reciting the Holy Quran, prayer, and supplications hoping that there would be more opportunities for them to be forgiven by Allah on this special day. One of the best deeds performed by Shia Muslims is reciting Imam Hussain’s (AS) supplication of Arafah, which best represents the spirit of this day. Contemplation on this amazing supplication which encompasses facts about monotheism and its degrees will ultimately bring us closer to Allah.

The supplication of Arafah by Imam Hussain (AS)

In this supplication, we first praise God in a loving and friendly manner. Then we count the blessings God has bestowed upon us, and after confessing our misdeeds and sins, we ask Allah to forgive them. That is when we put forth our request to God. Now let’s recite and think about some of the most beautiful verses from this supplication (Dua): (You may also find the audio and the English subtitle of this supplication here.)

Arafah, a better opportunity to praise Allah

“Praise be to Allah Whose determination cannot be repelled by anything, whose gifts cannot be stopped by anything, and Whose making cannot be resembled by the making of anyone. He is the All-magnanimous, the All-liberal.”

A Path to Self-knowledge

“Even before that (before you showed me the right path), You had compassion on me, through Your excellent conferral and Your affluent bestowals. So, You fashioned my creation from semen that gushed forth and put me up in triple darkness among flesh, blood, and skin. You have not made me witness my creation, and You have not referred any part of my creation to me.”

Getting trained at the Divine school of God

“So, Exalted be You, O All-merciful, O All-beneficent. When I commenced (my life) by pronouncing words, You perfected for me the affluent bestowals and brought me up to an increase every year. When my creation was accomplished, and my power became straight, You put me under the obligation of Your Claim, which is that You inspired me with recognition of You and alarmed me by the wonders of Your wisdom.”

Counting God’s blessings

“As You created me from the best of soil, You, my God, have not wanted for me to have a certain favor (and to be deprived of another) and You, therefore, provided me with the various kinds of living and types of wealth, out of Your great and grand conferral upon me, and Your eternal kindness to me.”

Testimony to the boundless Divine blessings

“And I bear witness, O my God, with my true belief, and the fortitude of the determinations of my conviction and the purity of my open belief in Your Oneness and the essence of the secret of my conscience, and the ties of the canals of the light of my sight, and the lines of my forehead and the hallows of the courses of my breath, and the (nasal) cavities of my nose, and the courses of the meatus of my hearing, and whatever my two lips hide and cover up, …”

Human inability to thank Allah

“I bear witness) that if I try my best and strive throughout all ages and at all times, if I live them, to thank properly only one of Your favors, I will not be able to do that, except through a favor of You, which also requires me to thank You for it, once again with new thanking and with praise that is newly acquired and newly prepared.”

The opportunity to repent and ask for forgiveness

“It is I who did wrong. It is I who had evil intention…I now acknowledge of my sins; so, (please) forgive them to me.”

Arafah is one of the best days to turn to God with sincere repentance. Allah, on this day, accepts the repentance of His servants and grant them forgiveness if they are truly regretful and determined to give up their sins.

The demands of a nobleman

“O Allah, (please) make me fear You as if I can see You. Make me happy by fearing You. Do not make me unhappy by disobeying You. Choose for me through Your decree. so that I will not long for hastening that which You have delayed or delaying that which You would hasten.”

Eventually, you will find yourself immersed in the ocean of Allah’s mercy, which is what a true believer always seeks.

 “O Allah, Verily, You are the nearest of those who are prayed, You are the promptest of those who may respond, the most generous of those who may pardon, and the most responding of those who are asked. O All-beneficent of the world and the Hereafter, and All-merciful!”

References:

1. Arafah
2. Day of Arafah
3. Arafah supplication
4. supplication