Is it permissible for the Imam to wait for congregants in the last rukoo' (bowing) or the last tashahhud (testification of faith) so that they may catch the congregational prayer?

It is disliked for the Imam to wait for someone who wishes to join him in ruku' (bowing) if this causes hardship to the ma'mumin (those praying behind him). If it does not cause hardship, then Ahmad said: "He may wait for him as long as it does not cause hardship to those behind him." The Malikis dislike it, unless the Imam fears significant harm from the latecomer, or if the latecomer is ignorant and would consider the rak'ah (unit of prayer) invalid if he missed its ruku'. As for the Imam waiting for a latecomer during the final tashahhud (testimony), Al-Nawawi recommended it, provided the three conditions related to waiting in ruku' are met.