He—may Allah have mercy on him—was asked:

“Is prayer valid when one stands ahead of the imam, or behind him in the mosque with a barrier between them?”

He answered:

Regarding a follower praying ahead of the imam, the scholars hold three opinions:

The first is that the prayer is valid in all cases, even if it is said to be disliked. This is the well-known position in Mālik’s school and al-Shāfiʿī’s earlier opinion.

The second is that it is invalid in all cases. This is the position of Abū Hanīfah, and the well-known position in the schools of al-Shāfiʿī and Ahmad.

The third is that it is valid when there is a legitimate excuse, but not otherwise. For example, if overcrowding prevents someone from performing the Friday prayer or funeral prayer except by standing ahead of the imam, then praying ahead of him is better than foregoing the prayer. This is the opinion of a group of scholars and is one position within the school of Ahmad and others. It is the most balanced and strongest of the opinions.