What is the ruling on straightening the rows after standing for the second, third, and fourth rak'ahs?

Straightening the rows in prayer is obligatory, meaning that the worshippers in their rows should be aligned such that no one is ahead of another. The rows must remain straight until the prayer is finished. If a row becomes uneven in the second or third rak'ah, then whoever has moved forward or backward must straighten themselves. It is permissible for someone who notices an irregularity to adjust their companion with their hand or alert them with a gesture. This movement is considered mustahabb (recommended) because it is for the benefit of the prayer.