The Messenger of Allah ﷺ said, "There are four traits, whoever possesses them is a pure hypocrite, and whoever possesses one of them has within him a trait of hypocrisy until he abandons it. When he speaks, he lies. When he promises, he breaks his promise. When he makes a covenant, he betrays it. And when he disputes, he behaves wickedly."
قال رسول الله ﷺ: أربع خلال من كن فيه كان منافقا خالصا: من إذا حدث كذب، وإذا وعد أخلف، وإذا عاهد غدر، وإذا خاصم فجر، ومن كانت فيه خصلة منهن كانت فيه خصلة من النفاق حتى يدعها.
Bukhari narrated it in Jizya and Truces (3178), and Muslim in Faith (58), both through Amash, from Abdullah bin Mura, from Masruq, from Abdullah bin Amr bin As, who said, then he related it.