Worship of God without fear and obedience to Him is empty (vain) hypocrisy.
Justice becomes vain and corrupt even as man is like the animals when it comes to the inevitability of death.
Frustration with this difficult life should force us to seek the God of eternity.
The wisdom of this world is futile in the face of death.
The vanity of seeking after wisdom, knowledge, and the new, without God.