Musnad Ahmad 31:341

Aswad ibn Amir narrated to us, he said: Abu Isra'il informed us, from Atiyyah, from Abu Sa'id al-Khudri, who attributed it to the Prophet (ﷺ), he said: "Indeed, a man may speak a word, intending no harm by it, only to make the people laugh, and because of it, he falls further than the distance between the heaven and the earth."