Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: Sayyiduna Sa'd bin Ubadah (may Allah be pleased with him) sought a ruling from the Messenger of Allah (peace and blessings be upon him) about a debt that his mother owed, and she had died before paying it. The Prophet (peace and blessings be upon him) said: "Pay it on her behalf."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5356