I heard Messenger of Allah ﷺ saying, "The rights of a Muslim on the Muslims are five: to respond to the salaam, visiting the sick, to follow the funeral processions, to accept an invitation, and to reply to those who sneeze. (see Hadith 1239)  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ حَقُّ الْمُسْلِمِ عَلَى الْمُسْلِمِ خَمْسٌ رَدُّ السَّلاَمِ وَعِيَادَةُ الْمَرِيضِ وَاتِّبَاعُ الْجَنَائِزِ وَإِجَابَةُ الدَّعْوَةِ وَتَشْمِيتُ الْعَاطِسِ