'Works' in the Bible

I have seen all the works which have been done under the sun, and behold, all is vanity, a futile grasping and chasing after the wind.

I made great works: I built houses for myself; I planted vineyards for myself;

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?

For I have taken all this to heart, exploring and examining it all, how the righteous (those in right standing with God) and the wise and their deeds are in the hands of God. No man knows whether it will be love or hatred; anything awaits him.

Go your way, eat your bread with joy and drink your wine with a cheerful heart [if you are righteous, wise, and in the hands of God]; for God has already approved and accepted your works.