What is the ruling if the regular imam is late for the prayer?

Question:
He says: I and a group came to the mosque at the time of the Maghrib prayer and found it locked. The time for prayer entered, and the iqamah was called in the other mosques. We called the iqamah ourselves and prayed in the outer courtyard. During the prayer, the imam entered with a group, and they opened the mosque from the inside and called the iqamah for another congregation, so there became two congregations in the mosque. After finishing the prayer, the imam disapproved of our prayer. The question is: who is right?

Answer:
If they were late, then they are the ones who are wrong, and you are right. You are excused, and they are the ones who erred if they were late in coming at the time of prayer. But if they were not late, then you are the ones who rushed and erred. A congregation is not established in a mosque where there is a regular congregation. It is necessary that the Muslims agree on one imam in the mosque. It is obligatory that you wait until the imam and the congregation arrive and you pray with them, and do not rush.