While we were with the Messenger of Allah ﷺ, a man from the tribe of Banu Salama came to him and asked, "Messenger of Allah, is there any way I can still show kindness to my parents after their death?"He replied, "Yes. Praying for them, seeking forgiveness on their behalf, fulfilling their promises after them, maintaining ties with relatives who can only be reached through them, and honoring their friends."
حدثنا إبراهيم بن مهدي وعثمان بن أبي شيبة ومحمد بن العلاء المعنى قالوا حدثنا عبد الله بن إدريس عن عبد الرحمن بن سليمان عن أسيد بن علي بن عبيد مولى بني ساعدة عن أبيه
بينا نحن عند رسول الله ﷺ إذ جاءه رجل من بني سلمة فقال يا رسول الله هل بقي من بر أبوي شيء أبرهما به بعد موتهما قال نعم الصلاة عليهما والاستغفار لهما وإنفاذ عهدهما من بعدهما وصلة الرحم التي لا توصل إلا بهما وإكرام صديقهما
Its isnad is hasan. Ibn Majah reported it in the chapters on manners, in the chapter "Honor those whom your father used to honor," hadith 3664, from the hadith of Abdullah bin Idris, through this route. Ibn Hibban graded it sahih, hadith 2030, as did Hakim, 4/154, 155, and Dhahabi agreed with him.