Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that the Messenger of Allah (peace and blessings be upon him) said to them: "I do not ask you for any reward for this, except that you honour me because of my kinship with you, and that you safeguard the kinship that is between me and you."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12181