How did the Prophet's — may God's prayers and peace be upon him — prayer used to be?

The description of the Prophet's prayer, peace and blessings be upon him, can be summarized as follows: Prayer begins by facing the Kaaba, with exceptions for the traveler, the sick, and the warrior. This is followed by standing for those who are able. The worshiper says the opening takbir (takbirat al-ihram) while raising his hands, then places his right hand over his left on his chest. He shows humility in his prayer and looks at the place of his prostration. He begins the recitation with established supplications, then seeks refuge (ta'awwudh) and says Bismillah silently, and recites Al-Fatiha aloud or silently depending on the prayer. It is sunnah to recite another surah after it.

This is followed by bowing (ruku') with calmness (ṭuma'nīnah), and saying "Subhan Rabbiyal-Adheem" (Glory be to my Lord, the Most Great). Then, he straightens up from bowing, saying "Sami'allahu liman hamidah" (Allah hears those who praise Him) and "Rabbana wa lakal-hamd" (Our Lord, and to You be all praise). Then, he prostrates (sujud) on the seven limbs with firmness and balance, saying "Subhan Rabbiyal-A'la" (Glory be to my Lord, the Most High) and making supplication. He sits between the two prostrations in the iftirash position (left foot laid flat, right foot upright) and makes supplication. These actions are repeated in the second rak'ah, which is shorter than the first.

After the second rak'ah, he sits for the first tashahhud in the iftirash position, and points with his index finger while moving it. Then, he stands for the third and fourth rak'ahs, in which he usually recites only Al-Fatiha.

Qunut (supplication) is prescribed in times of calamity (nawazil) and after bowing (ruku'). The Witr qunut is sometimes recited before the ruku'. He sits for the final tashahhud in the tawarruk position (left foot under the right leg, right foot upright), sends prayers upon the Prophet, peace and blessings be upon him, seeks refuge from four things, and supplicates for whatever he wishes.

The prayer concludes with the salutation (taslim) to the right, then to the left. Emphasis is placed on the importance of humility (khushu') and calmness (ṭuma'nīnah) in all pillars of the prayer.