as a personal favor to him. Rather, it was a form of instructing them—an order meant for their own benefit just like every other act of obedience for which they are rewarded. Indeed, the Prophet ﷺ receives a reward equal to theirs for everything they do, for it is authentically reported that he said: “Whoever calls people to guidance will receive a reward equivalent to the rewards of all who follow him, without those rewards being diminished in the least; and whoever calls people to misguidance will bear a burden of sin equivalent to the sins of all who follow him, without their burden being diminished in the least.” As the one who summoned the entire community to every path of guidance, he therefore enjoys a reward matching theirs for every good deed in which they follow him.
The same applies when they invoke blessings upon him: Allah sends ten blessings upon the one who does so, and the Prophet ﷺ gains a reward equal to theirs in addition to the benefit that comes to him from their prayers. Thus Allah grants them their full reward for that supplication, and whatever benefit reaches him through it is a grace bestowed upon him by Allah.
It is recorded in the Ṣaḥīḥ that he said: “No man supplicates for his brother in his absence without Allah appointing an angel over him who, each time he prays, says: ‘Āmīn—and the same for you.’” In another narration he said: “The supplication answered most quickly is the supplication offered by one believer for another when the latter is absent.”