John Calvin Commentary Psalms 148:11

"Kings of the earth and all peoples; Princes and all judges of the earth;" — Psalms 148:11 (ASV)

Kings of the earth, and so forth. He now turns his address to humanity, on whose behalf he had called for a declaration of God’s praises from creatures, both above and below. Since kings and princes are often blinded by the dazzling influence of their station, thinking the world was made for them and despising God in the pride of their hearts, he particularly calls them to this duty. By mentioning them first, he reproves their ingratitude in withholding their tribute of praise when they are under greater obligations than others.

Since all people are originally equal in their condition, the higher individuals have risen and the nearer they have been brought to God, the more sacredly they are bound to proclaim His goodness. The more intolerable, therefore, is the wickedness of kings and princes who claim exemption from this common rule, when they should instead instill it in others and lead the way.

He could have addressed his exhortation summarily to everyone at once, as indeed he mentions peoples in general terms. However, by specifying princes three times, he suggests that they are slow to discharge this duty and need to be urged to do it. Then follows a division according to age and sex, to show that all without exception are created for this purpose and should unitedly devote their energies to it.

As for old men, the more God has lengthened their lives, the more they should be engaged in singing His praises. But He joins young men with them, for though they may have less experience from long habit, it will be inexcusable if they do not acknowledge the great mercy of God in the vigor of their lives.

In speaking of girls or virgins, the particle גם, gam, also, is not merely a filler word but is added to make the words more emphatic. This conveys the truth that even young women—who, in that era, might not have been as liberally educated as men and were often considered primarily suited for domestic duties—would be neglecting their duty if they did not join with the rest of the Church in praising God. It follows that all, from the least to the greatest, are bound by this common rule.