On the night of the first Aqabah, they accept Islam and pledge alliance with the Prophet, which is the beginning of Islam among the Ansar.
What is the dawn of Islam among the Ansar like? – Part 1
What is the dawn of Islam among the Ansar like? Part 2
Ibn Ishaq said that Ibn Shihab Az-Zuhri related from ‘A’idhullah Abi Idrees Al-Khawlani that ‘Ubadah Ibn As-Samit narrated to him: “We gave our pledge to Allah’s Messenger, peace and blessings of Allah be upon him, on the night of the first ‘Aqabah that we will not worship anything besides Allah, we will not steal, we will not commit illegal sexual intercourse, we will not kill our children, we will not utter slander, invented by ourself, and we will not disobey him if he ordered us to do something good.” (The Prophet, peace and blessings be upon him, responded): “Whoever among you respects and fulfils this pledge, will be rewarded by Allah.
And if anyone of you commits any of these sins and is punished in this world then that will be his expiation for it, and if anyone of you commits any of these sins and Allah hides his sin, then his matter will rest with Allah: If He wills, He punishes him and if He wills He forgives him.” This Hadith has been collected in the Saheehain and other than them.
How many were you at the time? Abdur-Rahman asked his father
Ibn Ishaq related that Abdur-Rahman Ibn Ka‘b Ibn Malik said: I used to be a guide for my father when he became blind. Whenever I went out with him for the Jumu‘ah prayer and he heard the call to prayer, he would supplicate for Abu Umamah Asad Ibn Zurarah. He continued doing that for a while, supplicating for him upon hearing the call to prayer.
Then I said to myself: “By Allah, this is a deficiency on my part, shouldn’t I ask him (why)?” so I said to him, “ My father, why is it that whenever you hear the call to the prayer of Jumu‘ah you supplicate and ask Allah’s forgiveness for Abu Umamah?”
He said: “My son, this is because he held the Friday prayer for the first time for us at Hazmun-Nabeet of Harrah belonging to Banu Bayadah in Baqee‘, called Naqee‘ Al-Khadimat.” I asked him: “How many were you at the time?” He said: “Forty men.” Abu Dawood and Ibn Majah have related this Hadith through Muhammad Ibn Ishaq, may Allah have mercy on him.