'Rejoice' in the Bible

So I have seen that there is nothing better than that a man should be happy in his own works and activities, for that is his portion (share). For who will bring him [back] to see what will happen after he is gone?

There is no end to all the people; to all who were before them. Yet those who come later will not be happy with him. Surely this also is vanity (emptiness) and chasing after the wind.

Also, every man to whom God has given riches and possessions, He has also given the power and ability to enjoy them and to receive [this as] his [allotted] portion and to rejoice in his labor—this is the gift of God [to him].

Yes, if a man should live many years, let him rejoice in them all; yet let him remember the days of darkness, for they will be many. All that is to come will be futility.

Rejoice, young man, in your childhood, and let your heart be pleasant in the days of your young manhood. And walk in the ways of your heart and in the desires of your eyes, but know that God will bring you into judgment for all these things.