Catching the imam while he is bowing: saying the takbir of entering prayer, then bowing without saying the takbir for bowing

Question:
Sometimes I catch up with the imam in the congregational prayer when he is about to begin a rak'ah. I say the takbir of entering prayer once, but I forget the takbir for the rak'ah. Is the prayer valid, or must I repeat the rak'ah?

Answer:
Yes, the prayer is valid because the takbir for bowing is considered a recommended practice (sunnah) in this situation. If you leave it out, you owe nothing. However, the takbir of entering prayer is essential because it is a pillar of the prayer. You should first say the takbir of entering prayer while standing, then bow. If you do so with a takbir, that is better; if you do so without a takbir, that is permissible in this situation. Yes.