Silsilah as-Sahihah 746 — Rights of Muslims over each other

It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Noble Prophet (peace and blessings of Allah be upon him) said: "These three rights are obligatory upon every Muslim: to visit the sick, to attend funerals, and when someone who sneezes says « «اَلْحَمْدُ لِلّٰهِ», to say to him «يرحمك الله» 'May Allah have mercy on you.'"