Musnad Ahmad 28:56

Waki' narrated to us, Ibn Abi Dhi'b narrated to us, from his maternal uncle Al-Harith ibn Abd al-Rahman, from Abu Salamah ibn Abd al-Rahman, from Abdullah ibn Amr, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) cursed the one who gives the bribe and the one who takes the bribe."