John Gill Commentary Ecclesiastes 8:6

"for to every purpose there is a time and judgment; because the misery of man is great upon him:" — Ecclesiastes 8:6 (ASV)

Because to every purpose there is time and judgment
There is a fit season, and a right and proper manner of doing everything that is to be done; see (Ecclesiastes 3:1–8) ; which a wise man discerns; and which when a man hits upon, it prevents a great deal of mischief, which for want of it comes upon men, as the following clause shows;

Some refer this to the punishment of the wicked, and to a future judgment. So the Targum, ``to every business there is a time good and evil, and according to the judgment of truth the whole world is judged;'' and to the same purpose Jarchi, ``there is a time fixed for the visitation of the wicked, and there is judgment before the Lord; this is vengeance or punishment;''

therefore the misery of man [is] great upon him;
He not observing the right time and manner of doing what he ought, brings much trouble upon himself; his days are few and full trouble, and every day has a sufficiency of evil in because of the evil of sin, the evil of misery presses upon him, and is a heavy burden on him.

Jarchi's note is, ``when the wickedness of a man is great, then cometh his visitation.''