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.
    

Looking at Imam Hussain (AS)'s movement and the incidents that took place on Karbala, one might wonder if Imam Hussain (AS) ever had the intention of going to war with Yazid or not. In what follows, we raise some questions that will reveal Imam Hussain (AS)'s real attitude toward war.

1. Why Would He Leave Medina to Mecca?

He did not wish to take the oath of allegiance of a ruthless and corrupt person as Yazid, so he decided to peacefully migrate from Medina to Mecca in which many people had not accepted Yazid’s oath of allegiance yet. In his will which he wrote before leaving Medina, he says:

“I am not leaving here out of selfishness or with the aim of oppression or corruption, but for the sake of improving Muslims’ condition of life. I want to enjoin the right (Amr bi-l-ma’ruf) and forbid the wrong (Nahy’ ani-l-munkar) and to act according to Prophet Muhammad (PBUH&HP)’s and Imam Ali’s (AS) way”.

2. Why Did Imam Hussain (AS) Take All His Property and His Family with Him?

His first motivation to leave Medina was migration, not war. So he left Medina to Mecca along with his family and companions without making any violent move against Yazid. On the day of Ashura on which Imam Hussain (AS) was martyred, 17 to 19 people of his family and relatives were among his companions, including some women and children. Among the martyrs of Karbala, also, there were five teenagers and children. One might ask, as Charles Dickens once asked if Imam Hussain (AS) were after worldly desires as taking over the throne, why would he take his family and children with him and risk their lives?

3. Why Would He even Go to Kufa? Should He Have Left Kufa People’s Letters Unresponded?

Imam Hussain (AS) had no intention of going to Kufa, but he was persuaded to do so by the many letters he received from Kufa people asking him to help them against Yazid’s tyranny. His speech in front of Hur’s army proves this fact: 

“O’ people! This is my last word to you so that there would be no excuse in Allah’s presence. I would not come to you if you had not sent your letters and messengers and asked me to come to you. You told me that you didn’t have a leader and wanted Allah to guide you through me. So, if you still keep your words, I will come to your city, and if you don’t want me to come, I will return.”

4. Why Did He Refuse to Fight with Hur’s Army Despite His Strength?

When surrendered by Hur and his army, Zuhair, one of Imam Hussain’s (AS) companions, suggested fighting them. Since they were not still much in number and Imam Hussain’s (AS) camp had the strength to defeat them. However, Imam Hussain (AS) rejected his view and told him that if there would be a war, he did not wish to be its initiator, though he would defend himself if necessary.

5. Why Would He Wish to Postpone the War even for One More Day

Imam Hussain (AS) wanted to postpone the war as much as possible, not because he was afraid of fighting, but to give the enemy more time to think twice about their wrong decision. So, when on the evening of the 9th of Muharram, Umar ibn Sa’ad gathered his army and got them ready for the war, he sent them a message and asked them to postpone the war until the day after and he spent the night praying to Allah.

Even on the very day of Ashura, Imam Hussain (AS) did his best to dissuade the enemy of choosing the wrong path and losing the God-given blessing of life for a ruthless tyrant as Yazid and his vain intentions. That is because Imam Hussain (AS) who was the spiritual leader of Muslims and cared about their fate more than his own life, found it his responsibility to guide them toward what is right before it was too late [i]. 

Notes:

[i] For more information see Salam Islam's ebook: 40 Points about Imam Hussain (AS) and the Event of Karbala