'Works' in the Bible

I have seen all the works that are done under the sun, and behold, all is vanity and pursuit of the wind.

I made me great works; I builded me houses; I planted me vineyards;

Then I looked on all the works that my hands had wrought, and on the labour that it had cost me to do them; and behold, all was vanity and pursuit of the wind, and there was no profit under the sun.

And I have seen that there is nothing better than that man should rejoice in his own works; for that is his portion; for who shall bring him to see what shall be after him?

For all this I laid to my heart and indeed to investigate all this, that the righteous, and the wise, and their works, are in the hand of God; man knoweth neither love nor hatred: all is before them.

Go, eat thy bread with joy, and drink thy wine with a merry heart; for God hath already accepted thy works.