Bukhari

Hadith Commentary:
The Battle of Badr was the first battle that the Muslims fought against the disbelievers, in which many prominent leaders of the disbelievers were killed.
The mention of the Night of Aqabah has already occurred above.
This was the night in which the Ansar made a firm pledge of companionship to the Prophet (sallallahu alayhi wa sallam), and he appointed twelve leaders (naqib) from among the Ansar.
It was a historic night in which the foundation of the strength of Islam was laid, and the Prophet (sallallahu alayhi wa sallam) attained inner peace. That is why Ka'b (radi Allahu anhu) considered participating in it even better than participating in the Battle of Badr.
The hadith mentions Aqabah.
Aqabah refers to a mountain pass; this pass was located between the area of al-Hara and Mina, among long mountain ranges. It was at this very place that twelve individuals from Madinah, in the twelfth year of Prophethood, had the honor of presenting themselves before the Messenger of Allah (sallallahu alayhi wa sallam) and embraced Islam. This is called the First Pledge of Aqabah (Bay'at al-Aqabah al-Ula).
For the education of these people, the Prophet (sallallahu alayhi wa sallam) sent Mus'ab ibn 'Umayr (radi Allahu anhu) with them to Madinah, who was the beloved son of a very wealthy family.
However, after accepting Islam, he forgot all worldly comforts and luxuries. He achieved great success in Madinah.
He stayed there at the house of As'ad ibn Zurara.
The following year, in the thirteenth year of Prophethood, seventy-three men and two women set out from Yathrib and came to Makkah, and in this very pass, they had the honor of presenting themselves in the court of the Messenger (sallallahu alayhi wa sallam).
The Messenger of Allah (sallallahu alayhi wa sallam) illuminated them with his radiant sermon, and these people requested the Prophet (sallallahu alayhi wa sallam) to come to Madinah.
He accepted this request, upon hearing which they were extremely pleased and pledged allegiance at his blessed hand.
Bara' ibn Ma'rur (radi Allahu anhu) was the first elder who pledged allegiance that night; this is called the Second Pledge of Aqabah (Bay'at al-Aqabah al-Thaniyah).
From among these individuals, the Prophet (sallallahu alayhi wa sallam) appointed twelve as leaders (naqib), just as 'Isa ibn Maryam (alayhis salam) had appointed twelve leaders for himself. The honored names of the twelve leaders of the Prophet (sallallahu alayhi wa sallam) are as follows:
(1) As'ad ibn Zurara (2) Rafi' ibn Malik (3) 'Ubadah ibn Samit (4) Sa'd ibn Rabi' (5) Mundhir ibn 'Amr (6) 'Abdullah ibn Rawahah (7) Bara' ibn Ma'rur (8) 'Amr ibn Haram (9) Sa'd ibn 'Ubadah — all of these were from the tribe of Khazraj — (10) Usayd ibn Hudayr (11) Sa'd ibn Khaythamah (12) Abu al-Haytham ibn al-Tihan — these three were from the tribe of Aws, radi Allahu anhum ajma'in.
O Allah, on the Day of Resurrection, gather us sinners together with all these noble elders.
Amin.

Hadith Commentary:
1.
‘Aqabah is the name of a mountain pass in Mina.
During the days of Hajj, the Messenger of Allah (sallallahu alayhi wa sallam) would meet with various tribes in Mina and invite them to Islam. On one occasion, he met with a few people from the tribe of Khazraj near ‘Aqabah.
He invited them to Islam, which they accepted.
The following year, twelve men from the Ansar came.
Among them was ‘Ubadah ibn Samit (radi Allahu anhu).
They too presented themselves before the Messenger of Allah (sallallahu alayhi wa sallam) at the place of ‘Aqabah and pledged allegiance to him.
This is commonly referred to as the First Pledge of ‘Aqabah (Bay‘at al-‘Aqabah al-Ula).
The next year, seventy men came for Hajj.
The Messenger of Allah (sallallahu alayhi wa sallam) promised to meet them at ‘Aqabah:
When they gathered, the Messenger of Allah (sallallahu alayhi wa sallam) arrived and there they pledged allegiance to him.
This is called the Second Pledge of ‘Aqabah (Bay‘at al-‘Aqabah al-Thaniyyah). There, he appointed one naqib (leader) for each small tribe. 2.
Ka‘b (radi Allahu anhu) says that although the Battle of Badr is very renowned in the spread of Islam, in his view, the Pledge of ‘Aqabah is more virtuous, because it was ‘Aqabah that became the cause for the advancement of Islam, and through it the foundation of Islam was strengthened and made firm.