While we were with the Prophet ﷺ, a man from Banu Salama came to him and asked, "Messenger of Allah, is there anything left of dutifulness to my parents that I can do for them after their death?"He replied, "Yes. Praying for them, seeking forgiveness for them, fulfilling their pledges after their death, honoring their friends, and maintaining the ties of kinship that can only be reached through them."
حدثنا علي بن محمد حدثنا عبد الله بن إدريس عن عبد الرحمن بن سليمان عن أسيد بن علي بن عبيد مولى بني ساعدة عن أبيه
بينما نحن عند النبي ﷺ إذ جاءه رجل من بني سلمة فقال يا رسول الله أبقي من بر أبوي شيء أبرهما به من بعد موتهما قال نعم الصلاة عليهما والاستغفار لهما وإيفاء بعهودهما من بعد موتهما وإكرام صديقهما وصلة الرحم التي لا توصل إلا بهما
Its isnad is hasan. Abu Dawud reported it in the Book of Manners, chapter on kindness to parents, no. 5142, from the hadith of Ibn Idris, with this wording. Ibn Hibban and Hakim (4/154, 155) graded it sahih, as did Dhahabi, and Munziri indicated that it is hasan (Targheeb 3/323).