For all his days are sorrows, and his travail grief; yea, his heart taketh not rest in the night. This is also vanity. His days are sorrows - What a picture of human life where the heart is not filled with the peace and love of God! All his days are sorrows; all his labors griefs; all his nights restless; for he has no portion but merely what earth can give; and that is embittered by the labor of acquisition, and the disappointment in the using.
This is also vanity - Emptiness of good and substantial misery.