Matthew Henry on Psalms 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.