Virtue and context
Abu Hurairah (raḍiy Allāhu ʿanhu) narrated that the Prophet ﷺ instructed the person who sneezes to praise Allah. The Muslim who hears that praise should ask Allah to have mercy upon the sneezer, who then responds by asking Allah to guide the other person and set their condition right.
The Messenger of Allah ﷺ explained that Allah loves sneezing and dislikes yawning. A Muslim who hears another praise Allah after sneezing is required to respond, while yawning should be restrained because it is from Shaytan. On another occasion, two men sneezed before the Prophet ﷺ; he responded to the one who praised Allah and not to the one who remained silent.
The Prophet ﷺ also counted responding to a sneezer who praises Allah among the six rights Muslims owe one another, together with greeting, accepting invitations, giving sincere advice, visiting the sick, and following the funeral procession.