'Works' in the Bible

With respect to my extravagant works, I built houses for myself; I planted vineyards for myself.

Every person works for his own self-interests, but his desires remain unsatisfied.

I saw all of it as the activity of God. Frankly, a human being cannot understand what happens on earth, because however hard a man works to discover it, he will not find out. Despite what he thinks he knows, he will not be able to figure it out.