It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever asks you by Allah, give to him; whoever seeks refuge with you by Allah, grant him refuge; whoever invites you, accept his invitation; and whoever gives you even a trotter as a gift, accept it."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13423