What is the ruling on a student reserving a seat for his colleague in a crowded lecture, and is that considered contrary to justice? And is it considered a lie to tell someone who asks about the seat that it is not vacant? And what should we do if the action is impermissible?

The most deserving of a seat in a study hall is the one who arrived there first among the students. It is not permissible for a student or their friend to reserve a place and deprive someone who arrived earlier. Preventing someone who arrived earlier from sitting by telling them the spot is not empty is considered a lie. Repentance for this involves regretting the action, abandoning such behavior, and resolving never to return to it.