Moussar sur L’Ecclésiaste 1:14

Shlomo Hamelech, peace be upon him, wrote in Koheles, “I have seen all the deeds that are done beneath the sun and indeed they are all vapor and a shattering of the spirit” (1:14). That is, if the vapor of a deed is blemished it does not ascend beyond the sun to the higher regions but floats about beneath the sun. Everything that is done in the world produces vapor. Just as speech produces vapor so do deeds. The vapor of good deeds ascends On High immediately, where it is crowned and becomes a defender for the doer before the Holy One Blessed is He. But if a person performs vain deeds the vapor floats about in this world. Then as soon as his soul exits his body the vapor takes hold of his soul and casts it several parsaos, afflicting it greatly. This is what King Shlomo meant when he said, “I have seen all the deeds that are done beneath the sun and indeed they are all vapor and a shattering of the spirit.” That is, he saw those deeds the vapor of which does not ascend above the sun to the higher regions but floats about beneath the sun. It is then that a person brings about his own detriment, especially if he misused his faculty of speech, uttering unseemly things about his fellow without cause. The vapor of these utterances then goes and accuses him.