Musnad Ahmad 30:2036

Ishaq ibn Isa narrated to us, he said: Hammad ibn Salamah narrated to us, from Dawud ibn Abi Hind, from Sa’id ibn al-Musayyib, from Abu Hurairah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Three [traits] are in the hypocrite, even if he prays, and even if he fasts, and even if he claims that he is a Muslim: when he speaks, he lies; when he promises, he breaks [his promise]; and when he is entrusted, he betrays."