John Calvin Commentary Psalms 75:8

"For in the hand of Jehovah there is a cup, and the wine foameth; It is full of mixture, and he poureth out of the same: Surely the dregs thereof, all the wicked of the earth shall drain them, and drink them." — Psalms 75:8 (ASV)

For in the hand of Jehovah there is a cup. The Psalmist here applies that judgment, about which he has just spoken, more directly for the benefit of the godly. He affirms that the purpose for which God reigns is so that no iniquity may remain unpunished; but rather, that when wicked men have broken through all restraint and abandoned themselves to wickedness, He may bring them to the punishment they deserve.

From this we learn again what understanding we should have of God's providence—namely, that we should regard it as exercising its control with an ever-present power over every part of our life. Therefore, it is asserted that God has a cup in His hand with which to make the wicked drunk.

The word חמר, chamar, signifies full of dregs, and also red. Since red wine among the Jews was the strongest and sharpest, we may suppose that it is referred to here; and the analogy is very fitting, which represents God as having in His hand wine of a highly intoxicating character, with which to make the ungodly drunk, even to death.

It is implied that the swiftness of divine vengeance is incredible, resembling the speed and power with which strong wine penetrates to the brain, producing either madness or kindling a fever. For this reason it is said that the wine in God’s cup is red, as it is said in Proverbs 23:31,

“Look not upon the wine when it is red in the cup.”

Nor is it an objection to this that it is described a little later as full of mixture. These two things are not inconsistent with each other: first, that the wicked are suddenly made drunk with God's vengeance; and, secondly, that they drink it down to the very dregs, until they perish.

Some offer a different explanation of the term mixture, considering—though without any good reason—the allusion to be to the custom prevalent in warm climates of diluting wine with water. This expression, it is full of mixture, was instead added to give additional force to the prophet's statement; his purpose was to compare the vehemence and fury of God’s wrath to spiced wine. By these figures, he intimates that it will be impossible for the ungodly to escape drinking the cup that God will put into their hands, and that they will be compelled to drain it to the last drop.