I know that there is nothing better for them than to rejoice and do good while they live,
We have seen what changes there are in the world, and must not expect to find the world more sure to us than it has been to others. Now here Solomon shows the hand of God in all those changes; it is he that has made every creature to be that to us which it is, and therefore we must have our eye always upon him. I.
Commenting on Ecclesiastes 3:11-15
I know that there is no good in them,.... In these things; as the Arabic version; in the creatures, as Jarchi; in all sublunary enjoyments; in everything the wise man had made a trial of before, as natural Wisdom and knowledge, worldly pleasure, riches, and wealth; the "summun bonum", or happiness of men, did not lie in these things; this he knew by experience, and...
in them--in God's works (Ecc 3:11), as far as relates to man's duty. Man cannot fully comprehend them, but he ought joyfully to receive ("rejoice in") God's gifts, and "do good" with them to himself and to others. This is never out of season (Gal 6:9-10). Not sensual joy and self-indulgence (Phi 4:4; Jam 4:16-17).