Then I looked on all the works that my hands had made, and on the labor that I had expended on it: and, behold, all was vanity and like grasping the wind, and there was no profit under the sun.

Come unto me, all you that labor and are heavy laden, and I will give you rest.

For we know that the whole creation groans and travails in pain together until now.

Man

So I returned, and considered all the oppressions that are done under the sun: and behold the tears of such as were oppressed, and they had no comforter; and on the side of their oppressors there was power; but they had no comforter.

That which is far off, and exceedingly deep, who can find it out?

The eye

There is one alone, and there is not a second; yea, he has neither child nor brother: yet is there no end of all his labor; neither is his eye satisfied with riches; neither says he, For whom do I labor, and deprive my soul of good? This is also vanity, yea, it is a heavy travail.

He that loves silver shall not be satisfied with silver; nor he that loves abundance, with increase: this is also vanity.

My soul shall be satisfied as with marrow and fatness; and my mouth shall praise you with joyful lips:

Sheol and destruction are never full; so the eyes of man are never satisfied.

The leach has two daughters, crying, Give, give. There are three things that are never satisfied, yea, four things say not, It is enough:

Blessed are they who do hunger and thirst after righteousness: for they shall be filled.

They shall hunger no more, neither thirst any more; neither shall the sun strike them, nor any heat.

General references

Since there are many things that increase vanity, how is man the better?