(16) When I thought . . .--i.e., when I reflected in order to know this--when I tried to think the matter out, get at the bottom of it. (For the sense of the verb, comp. Psalm 78:5; Proverbs 16:9.)

It was too painful.--See margin.

Verse 16. - When I thought to know this; literally, and I meditated, that I might understand this. A process of careful thought and consideration is implied, during which the psalmist tried hard to understand the method of God's government, and to explain to himself its seeming anomalies. But he says, It was too painful for me. He did not succeed; he was baffled and perplexed, and the whole effort was a pain and a grief to him.

73:15-20 The psalmist having shown the progress of his temptation, shows how faith and grace prevailed. He kept up respect for God's people, and with that he restrained himself from speaking what he had thought amiss. It is a sign that we repent of the evil thoughts of the heart, if we suppress them. Nothing gives more offence to God's children, than to say it is vain to serve God; for there is nothing more contrary to their universal experience. He prayed to God to make this matter plain to him; and he understood the wretched end of wicked people; even in the height of their prosperity they were but ripening for ruin. The sanctuary must be the resort of a tempted soul. The righteous man's afflictions end in peace, therefore he is happy; the wicked man's enjoyments end in destruction, therefore he is miserable. The prosperity of the wicked is short and uncertain, slippery places. See what their prosperity is; it is but a vain show, it is only a corrupt imagination, not substance, but a mere shadow; it is as a dream, which may please us a little while we are slumbering, yet even then it disturbs our repose.When I thought to know this,.... How to reconcile the prosperity of the wicked, and the afflictions of the righteous, to the perfections of God, and his wise providence in the government of the world, by the mere dint of reason, without consulting the sacred oracles, or his own and others' experience:

it was too painful for me: too laborious and toilsome, a work he was not equal to; "hic labor, hoc opus"; see Ecclesiastes 8:17.