The Prophet ﷺ said, "There are four traits, whoever possesses all of them is a pure hypocrite, and whoever possesses one of them has a trait of hypocrisy until he abandons it. When entrusted, he betrays the trust. When he speaks, he lies. When he makes a covenant, he breaks it. And when he disputes, he behaves wickedly."
أن النبي ﷺ قال: أربع من كن فيه كان منافقا خالصا، ومن كانت فيه خصلة منهن كانت فيه خصلة من النفاق حتى يدعها: إذا اؤتمن خان، وإذ حدث كذب، وإذا عاهد غدر، وإذا خاصم فجر.
Bukhari narrated it in the Book of Faith (34) and Muslim in the Book of Faith (58), both through Sufyan, from Amash, from Abdullah bin Mura, from Masruq, from Abdullah bin Amr, who said, and then mentioned it. The wording given is that of Bukhari, and Muslim's wording is similar.