Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Sahl bin Sa’d (may Allah be pleased with him), he says that the Messenger of Allah (peace and blessings of Allah be upon him) said: “Beware of those sins which are considered insignificant. The example of those sins which are regarded as trivial is like a group of people who camped in a valley; one man brought a stick, another brought another stick, until (so many sticks were gathered that) they baked their bread with them. And indeed, when the reckoning of minor sins is taken from the one who committed them, they will destroy him.”