Ibn Abi Laila reported: The prayer was made obligatory in three stages. Our companions narrated to us that the Messenger of Allah (ﷺ) said: "I would love for the prayer of the Muslims—or he said the believers—to be unified as one, to the extent that I almost thought of sending men out into the houses to call the people when the time for prayer is due, and I almost thought of ordering men to stand upon the fortresses to call the Muslims when the time for prayer is due, until they diminished or almost diminished."
He said: Then a man from the Ansar came and said: "O Messenger of Allah, when I returned—seeing your concern—I saw a man as though he were wearing two green garments. He stood upon the mosque, gave the call to prayer (adhan), then sat for a moment, then stood and said something similar, except that he said: 'Qad qamatis-salah' (Prayer has begun). If not for people saying—Ibn al-Muthanna said: 'for you to say'—that I was awake and not asleep, I would have said that I was awake and not asleep."
The Messenger of Allah (ﷺ) said—and Ibn al-Muthanna said: "May Allah show you something good" (whereas 'Amr did not mention: "May Allah show you something good"): "Go and tell Bilal to give the call to prayer."
Umar said: "Indeed, I saw the exact same thing that he saw, but when I was preceded, I felt shy."
And our companions narrated: A man used to come and ask, and he would be informed of the part of the prayer he had missed. They used to stand with the Messenger of Allah (ﷺ), among those standing, bowing, sitting, and praying with the Messenger of Allah (ﷺ).
Ibn al-Muthanna said that 'Amr narrated to me: Husayn narrated it to me from Ibn Abi Laila until Mu'adh came. Shu'bah said: I heard it from Husayn, who said: "I consider him to be in no other state than this, so do likewise."
Abu Dawud said: Then I returned to the tradition of 'Amr b. Marzuq. He said: Mu'adh came and they pointed toward him—Shu'bah said: I heard this from Husayn—and Mu'adh said: "I do not consider myself to be in any state except that I am upon it." He said: Indeed, Mu'adh has established a sunnah for you, so do likewise.
And our companions narrated: When the Messenger of Allah (ﷺ) arrived in Madinah, he commanded them to fast for three days, and then Ramadan was revealed. They were a people who were not accustomed to fasting, and fasting was difficult for them. Whoever could not fast would feed a needy person. Then this verse was revealed: {Whoever of you is present for the month, let him fast it} [Al-Baqarah: 185]. The concession was given to the sick and the traveler, and they were commanded to fast.
And our companions narrated: A man, if he broke his fast and slept before eating, would not eat until morning. Umar ibn al-Khattab wanted [to be intimate with] his wife, but she said, "I have slept." He thought she was making an excuse, so he approached her. Then a man from the Ansar came and wanted food, and they said, "Wait until we heat something for you," and he fell asleep. When morning came, this verse was revealed to him: {Permitted for you on the night of fasting is sexual relations with your wives} [Al-Baqarah: 187].