Majma al-Zawaid — Hadith 17462

Sayyiduna Sahl bin Sa'd (may Allah be pleased with him) narrates this saying of the Prophet (peace and blessings be upon him): "Beware of trivial sins, for the example of trivial sins is like that of people who camp in a valley. One person brings a stick, another person brings another stick, until there is enough wood for them to bake their bread. Such is the example of trivial sins too (when they accumulate greatly): when the one who commits them is taken to account for them, they will destroy him."
Ahmad recorded it, and its narrators are the narrators of the Sahih. Al-Tabarani recorded it in all three of his books through two routes; the narrators of one of them are the narrators of the Sahih, except Abd al-Wahhab bin Abd al-Hakam, and he is thiqah (trustworthy).