A latecomer has to follow the Imam

Q 1: Is it permissible for the Imam (the one who leads congregational Prayer) of a Masjid (mosque) to refuse to lead a Salah (Prayer) if he is present in the Masjid?

A: It is not permissible for the Imam of a Masjid to refuse to lead people in a Salah if he is present in the Masjid, unless he has a lawful excuse or reason that requires him to delegate someone else to lead the Salah. If this is the case, he should delegate someone who is qualified to lead the Salah and he should perform the Salah behind him as a Ma'mum (a person being led by an Imam in Prayer). He may delegate whoever he sees as the best person to lead the Salah instead of him, not just to excuse (Part No. 7; Page No. 425) himself, but to have the best person as the Imam. This would not be considered as a refusal to lead the Salah.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.