Sahih al-Bukhari #6

آيَةُ الْمُنَافِقِ ثَلاَثٌ إِذَا حَدَّثَ كَذَبَ، وَإِذَا وَعَدَ أَخْلَفَ، وَإِذَا اؤْتُمِنَ خَانَ

Allah's Messenger (ﷺ) said, 'The signs of a hypocrite are three: Whenever he speaks, he tells a lie; whenever he makes a promise, he always breaks it; if you trust him, he proves to be dishonest.'