Al-Kāfi

Hadith 1021
brotherhoodrights
أَحْمَدُ بْنُ مُحَمَّدٍ عَنْ عَلِيِّ بْنِ الْحَكَمِ عَنْ مُثَنًّى الْحَنَّاطِ عَنْ إِسْحَاقَ بْنِ يَزِيدَ عَنْ أَبِي عَبْدِ اللَّهِ ( عليه السلام ) قَالَ إِنَّ مِنْ حَقِّ الْمُسْلِمِ عَلَى الْمُسْلِمِ أَنْ يُجِيبَهُ إِذَا دَعَاهُ .
2. Ahmad ibn Muhammad has narrated from Ali ibn al-Hakam from Muthanna’ al-Hannat from Ishaq ibn Yazid who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘It is of the rights of a Muslim on a Muslim to accept his invitation.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī