The author comes back to the rhetorical question of Psalm 49:5: why be afraid of wealthy opponents? Here it is put stronger: do not be afraid of someone who is rich, or one who is becoming richer.
His possessions only increase, and so what? They pass you by with their possessions, but that should not make you fearful. Compare this with Psalm 73:9, They set their mouths against the heavens, and their tongue struts through the earth.
Do not be afraid, for the lesson here is clear: the person with the big mouth will die and he cannot take his wealth along into death.
16 Be not afraid when a man becomes rich, when the glory of his house increases.