Hazrat Hisham bin Urwah narrates that my father, when entering the mosque and the Imam was in the state of bowing (ruku‘), he would perform ruku‘ before joining the row and then enter the row.

Hazrat Waqa says that I and Hazrat Saeed bin Jubair entered the mosque while the people were in the state of bowing (ruku‘). Both of us performed ruku‘ at the door and then, walking, joined the row.

Hazrat Yazid bin Abi Habib states that he saw Abu Salamah entering the mosque while the people were in the state of bowing (ruku‘), then he slowly walked and joined the row.

Hazrat Ata, regarding the person who enters the mosque and finds the people in the state of bowing (ruku'), says that when he has passed by the women, he should say Allahu Akbar and perform ruku', then while walking, join the row, and if he catches up with the prostration (sajdah) before that, then wherever he finds the prostration, he should perform it there.

Hazrat Usman bin Aswad narrates that I and Amr bin Tamim entered the mosque. The Imam had gone into ruku, so I and he also performed ruku, then while in the state of ruku, we walked and joined the row. When we completed the prayer, Amr said to me, "From whom have you heard what you just did being called permissible?" I said, "From Mujahid," and he said that he had seen Hazrat Ibn Zubair do so.

Hasan and Hazrat Hisham say that if a person enters the mosque and the people are in the state of bowing (ruku‘), then he should see: if before he reaches them, the people will raise their heads from ruku‘, then he should perform ruku‘ right there and join the row while walking.

Hazrat Abu Huraira says that do not say the Takbeer until you join the row.

Hasan was asked about the person who performs rukū‘ before joining the row. He replied that he should not perform rukū‘.

Hazrat Mughira says that I asked Ibrahim, "When I enter the mosque and the Imam is in the state of bowing (ruku'), can I perform ruku' without joining the row (saff)?" He replied, "You should not do so."

Hazrat Abu Hurairah says that when you enter the mosque and the Imam is in the state of bowing (ruku‘), do not say the takbeer until you join the row. Hazrat Abu Bakr says that if there is another person with him, he may perform ruku‘ before joining the row, but if he is alone, he should not perform ruku‘.