What is the ruling on the imamate of an imam who pulled a person forward to lead the congregational prayer after he (the imam) was late for the prayer time, knowing that one cannot complete the recitation of Al-Fatiha behind him due to his rapid recitation in the silent prayer?

The congregants should not establish the prayer before the regular Imam arrives. Rather, a messenger should be sent to him if he is nearby. If he is far away and it is highly probable that he will not attend, then they should pray, and in that case, the one most deserving of leading the prayer should be put forward. If the regular Imam arrives while the prayer has already been established, it is better for him to follow the one who was appointed in his place, and his imamate (leadership) of the people for the remainder of the prayer is valid. Some jurists are of the opinion that the congregant is not obliged to recite Al-Fatiha behind the Imam.