Furthermore, it is part of the Sunnah that when a greeting of salām is carried from one person to another, the recipient should answer, “wa ʿalayhi al-salām” (and upon him be peace). If he instead says, “ʿalayka wa ʿalayhi al-salām,” or “ʿalayhi wa ʿalayka al-salām,” that is also commendable, for the messenger who conveyed the salām has shown kindness and you repay him with a supplication.

Thus, when someone says to another, “Convey my salām to So-and-so,” and the request is fulfilled—“So-and-so sends you salām”—the addressee may reply, “ʿalayhi wa ʿalayka al-salām,” or simply, “wa ʿalayhi al-salām,” and stop there. The proof is that the Prophet ﷺ once told ʿĀʾishah, “This is Jibrīl; he conveys salām to you,” and she replied, “wa ʿalayhi al-salām.” This shows that when a greeting reaches you through another, you may respond with “wa ʿalayhi al-salām.”

Is it obligatory to pass on the greeting when someone says, “Give my salām to So-and-so,” or is it not? The scholars have explained: if you pledge to do so, it becomes binding, for Allah says, “Indeed, Allah commands you to render trusts to those entitled to them” (Q. 4:58). By agreeing, you have assumed a trust. If, however, he merely says, “Convey my salām to So-and-so,” and says no more, or you answer, “If I remember,” or the like, you are not bound—unless you later remember after having promised to greet him when you did remember.

Nonetheless, it is better not to burden others with such requests, for it may be difficult for them. One may instead say, “Give my salām to anyone who asks about me”; that is fine. But saddling someone with a specific instruction is of little benefit, for he may feel embarrassed and say, “Yes, I will pass it on,” even though he might not actually do so.