I heard Al-Bara' bin ʿAzib saying, "The Prophet ﷺ orders us to do seven things and prohibited us from doing seven other things." Then Al-Bara' mentioned the following:-- (1) To pay a visit to the sick (inquiring about his health), (2) to follow funeral processions, (3) to say to a sneezer, "May Allah be merciful to you" (if he says, "Praise be to Allah!"), (4) to return greetings, (5) to help the oppressed, (6) to accept invitations, (7) to help others to fulfill their oaths. (See Hadith No. 753, Vol. 7)  

أَمَرَنَا النَّبِيُّ ﷺ بِسَبْعٍ وَنَهَانَا عَنْ سَبْعٍ فَذَكَرَ عِيَادَةَ الْمَرِيضِ وَاتِّبَاعَ الْجَنَائِزِ وَتَشْمِيتَ الْعَاطِسِ وَرَدَّ السَّلاَمِ وَنَصْرَ الْمَظْلُومِ وَإِجَابَةَ الدَّاعِي وَإِبْرَارَ الْمُقْسِمِ  

The Prophet ﷺ said, "A believer to another believer is like a building whose different parts enforce each other." The Prophet ﷺ then clasped his hands with the fingers interlaced (while saying that).  

عَنِ النَّبِيِّ ﷺ قَالَ الْمُؤْمِنُ لِلْمُؤْمِنِ كَالْبُنْيَانِ يَشُدُّ بَعْضُهُ بَعْضًا وَشَبَّكَ بَيْنَ أَصَابِعِهِ