John Calvin Commentary Psalms 50:21

"These things hast thou done, and I kept silence; Thou thoughtest that I was altogether such a one as thyself: [But] I will reprove thee, and set [them] in order before thine eyes." — Psalms 50:21 (ASV)

These things hast thou done. Hypocrites, until they feel the hand of God against them, are ever ready to surrender themselves to a state of security, and nothing is more difficult than to awaken their fears. By this alarming language, the Psalmist aims to convince them of the certainty of destruction if they presume longer upon the forbearance of God, and thus provoke His anger even more, by imagining that He can favor the practice of sin.

The greatest dishonor that anyone can cast upon His name is that of impeaching His justice. Hypocrites may not venture to do this openly, but in their secret and corrupt imagination they picture God to be different from what He is, so that they may take opportunity from His imagined forbearance to indulge a false peace of mind, and escape the anxiety they could not fail to feel if they were seriously persuaded that God was the avenger of sin.

We have sufficient proof in the complacent security that hypocrites display, that they must have formed such false conceptions of God. They not only exclude His judicial character from their thoughts but also think of Him as the patron and approver of their sins. The Psalmist rebukes them for abusing the goodness and clemency of God by cherishing a vain hope that they may sin without punishment.

He warns them that before long they will be dragged into the light, and those sins that they would have hidden from the eyes of God will be set in all their enormity before their view. He will set the whole list of their sins in distinct order, for so I understand the expression to set in order, before them, and force them to confront them.