The Messenger of Allah ﷺ said, "Beware of trivial sins. They are like a group of people who camped in the bottom of a valley. One brought a stick, and another brought a stick, until they had gathered enough to bake their bread. Indeed, trivial sins, when their doer is held accountable for them, will destroy him."
قال رسول الله ﷺ: إياكم ومحقرات الذنوب، كقوم نزلوا في بطن واد، فجاء ذا بعود، وجاء ذا بعود، حتى أنضجوا خبزتهم، وإن محقرات الذنوب متى يؤخذ بها صاحبها تهلكه.
Ahmad (22808), Ramahurmuzi in al-Amthal (67), and Bayhaqi in al-Shuab (7267) all narrated it through the route of Anas bin Iyad, who said, "Abu Hazim narrated to me, from Sahl bin Saad," who said, then he mentioned it. Its chain of transmission is sahih.