Those who said: if you enter while the imam is prostrating, then prostrate

A Companion from Madinah narrates that the Prophet (peace and blessings be upon him) heard the sound of his sandals while he was in prostration. When he finished his prayer, he said: "Whose sandals did I just hear?" I said: "It was me." He said: "Then what did you do?" I said: "I found you in prostration, so I prostrated along with you." The Prophet (peace and blessings be upon him) said: "Do it like this, and do not count that rak'ah. Whoever finds me bowing, prostrating or standing should join me in the same state."

The same is reported through another chain.

Sayyiduna Ibn Umar (may Allah be pleased with them both) and Sayyiduna Zayd bin Thabit (may Allah be pleased with him) said: If a person finds the people when they have already raised their heads from bowing, he should say "Allahu Akbar", prostrate, and not count that rak'ah.

Al-Hasan and Ibrahim said, regarding a man who reaches the imam while he is in prostration: He should follow him and prostrate with him, and not go against the imam. And he should not count that rak'ah because of the prostrations; however, if he catches the bowing, he has gained the rak'ah.

Ibrahim said: In whatever state you find the imam, do not go against him.

Qatadah said: If you find the people in prostration, prostrate with them, but do not count that rak'ah.

Al-Sha'bi said: If you find the people in prostration, prostrate with them and do not count that rak'ah. Abu al-Aliyah said: Prostrate with them and count that rak'ah.

Sayyiduna Ibn Umar (may Allah be pleased with them both) said: In whatever state you find the imam, do as he does.

Ibrahim said: In whatever state you find the imam, do as he does.

Muhammad (Ibn Sirin) liked that, in whatever state a person finds the people during the congregational prayer, he should join them in it.

Al-Sha'bi said, regarding a man who reaches the people while they are in prostration: He should prostrate with them.

Al-Hasan and Ibn Sirin said: When the people have placed their foreheads on the ground, it does not befit a man to remain standing upright.

Urwah disliked that, while the imam is in prostration, a person who arrives for the prayer should remain standing upright. He should follow the imam.

Urwah bin al-Zubayr used to say: When one of you arrives at the congregation while the imam is in prostration, he should prostrate with the people and not count that rak'ah.

Sayyiduna Ali (may Allah be pleased with him) said: If you do not catch the bowing, do not count that rak'ah.

Sayyiduna Abdullah (bin Mas'ud) (may Allah be pleased with him) said: If you do not catch the bowing, do not count that rak'ah.