Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Accept the invitation of the one who invites, do not return a gift, and do not strike the Muslims."
Ahmad and al-Bazzar recorded it. In one narration of al-Bazzar the words are: "Accept the invitation of the one who invites when you are invited."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; the narrators of Ahmad are the narrators of the Sahih.