Hadith 4917
وَعَنِ ابْنِ عُمَرَ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِنَّ مِنْ أَبَرِّ الْبِرِّ صِلَةَ الرَّجُلِ أَهْلَ وُدِّ أَبِيهِ بَعْدَ أَن يولي» . رَوَاهُ مُسلم
Ibn Umar, may Allah be pleased with him, narrates that the Messenger of Allah, peace and blessings be upon him, said: "Indeed, after a man's father passes away, maintaining ties with his father's friends is the greatest act of goodness." Narrated by Muslim.