Q. How does one join the Imaam when the Imaam is in Ruku?
A. If one finds the Imaam in the bowing (Ruku) posture of Salaah, then one should recite the first Takbeer (Allahu Akbar) to enter the Salaah in the standing (Qiyaam) posture whilst raising one’s hands towards one’s ears, and then fold the hands below the navel. Thereafter, one should recite the second Takbeer (Allahu Akbar) to go into the bowing (Ruku) posture of Salaah and join the Imaam.
However, the Salaah will be valid if one recited the first Takbeer in the standing (Qiyaam) posture of Salaah and went straight into the bowing (Ruku) posture of Salaah without folding one’s hands below one’s navel and without reciting the second Takbeer to go into the bowing (Ruku) posture of Salaah. (Durarul Hukkaam 1/302-Kifaayatul Mufti 3/431)
Allah Ta’ala Knows Best
Mufti Ismaeel Bassa
This answer was collected from TheMufti.com, which is a fatwa portal managed by Mufti Ismaeel Bassa from South Africa.