91 For all this I considered  in my heart even to declare all this, that the righteous, and the wise, and their works, are in the hand of God: no man knoweth either love or hatred by all that is before them.
91 So I reflected on all this and concluded that the righteous and the wise and what they do are in God's hands, but no one knows whether love or hate awaits them.
91 But all this I laid to heart, examining it all, how the righteous and the wise and their deeds are in the hand of God. Whether it is love or hate, man does not know; both are before him.
91 Well, I took all this in and thought it through, inside and out. Here's what I understood: The good, the wise, and all that they do are in God's hands - but, day by day, whether it's love or hate they're dealing with, they don't know.
91 For I considered all this in my heart, so that I could declare it all: that the righteous and the wise and their works are in the hand of God. People know neither love nor hatred by anything they see before them.
91 This, too, I carefully explored: Even though the actions of godly and wise people are in God's hands, no one knows whether God will show them favor.
Matthew Henry's Commentary on Ecclesiastes 9:1
Commentary on Ecclesiastes 9:1-3
(Read Ecclesiastes 9:1-3)
We are not to think our searching into the word or works of God useless, because we cannot explain all difficulties. We may learn many things good for ourselves and useful to others. But man cannot always decide who are objects of God's special love, or under his wrath; and God will certainly put a difference between the precious and the vile, in the other world. The difference as to present happiness, arises from the inward supports and consolations the righteous enjoy, and the benefit they derive from varied trials and mercies. As far as the sons of men are left to themselves, their hearts are full of evil; and prosperity in sin, causes them even to set God at defiance by daring wickedness. Though, on this side death, the righteous and the wicked may often seem to fare alike, on the other side there will be a vast difference between them.