Here is what I have seen to be good and fitting: to eat and drink, and to find satisfaction in all the labor one does under the sun during the few days of life that God has given him—for this is his lot.
Solomon, from the vanity of riches hoarded up, here infers that the best course we can take is to use well what we have, to serve God with it, to do good with it, and take the comfort of it to ourselves and our families; this he had pressed before, Ecc 2:24; Ecc 3:22. Observe, 1.
Commenting on Ecclesiastes 5:18-20
Behold that which I have seen,.... Observed, considered and approved of, and which he recommended and excited attention to, and is as follows; it is good and comely for one to eat and to drink; to make use of the creatures God has given for service in a free and liberal manner, without excess, and with moderation; and not deprive a man's self of those...
Returns to the sentiment (Ecc 3:12-13, Ecc 3:22); translate: "Behold the good which I have seen, and which is becoming" (in a man). which God giveth--namely, both the good of his labor and his life. his portion--legitimately. It is God's gift that makes it so when regarded as such. Such a one will use, not abuse, earthly things (Co1 7:31).