Salawat · a Light

One prayer on him returns as ten

The Qur'an instructs believers to send prayers and peace upon the Prophet ﷺ, and he told them what happens when they do: whoever sends one prayer upon me, Allah sends ten upon him. That is the reason for the small formula written after his name throughout Muslim literature, sallallahu alayhi wa sallam, and represented in modern typesetting by a single character. Scribes have added it by hand in the margins of manuscripts for more than a thousand years. It is one of the few devotional acts with no fixed time, place, direction, state of purity or number attached to it, which is why it turns up in the middle of ordinary sentences.

Abu Hurayra · Qur'an 33:56

Source · Muslim 408