The Prophet (blessings and peace of Allah be upon him) instructed the Muslim if he sees something with his Muslim brothers that he admires, to pray for blessing for them. The scholars differed as to whether this command means that this should be repeated or not.

Whoever harms the Muslims or causes hardship to them, Allah will requite him for his deed in this world and the hereafter, or in one of them. He may repent, and whoever repents, Allah will turn to him in mercy.