John Calvin Commentary Psalms 89:45

"The days of his youth hast thou shortened: Thou hast covered him with shame. Selah" — Psalms 89:45 (ASV)

Thou hast shortened the days of his youth. Some would explain this sentence as meaning that God had weakened the king, so that he faded or withered away at his very entrance into the prime of youth, and was exhausted with old age before reaching manhood.

This exposition may be regarded as not improbable; but still, it is to be observed, for us to have a clearer understanding of the prophet's mind, that he does not speak exclusively of any one individual, but compares the state of the kingdom to the life of a man.

His complaint then amounts to this: that God caused the kingdom to grow old, and finally to decay, before it reached a state of complete maturity; its fate resembling that of a young man who, while still increasing in strength and vigor, is carried away by a violent death before his time.

This analogy is highly appropriate; for the kingdom, if we compare its state at that period with the Divine promise, had scarcely yet fully unfolded its blossom when, amidst its first advances, it was suddenly struck with a grievous decay, its freshness and beauty were defaced, and finally it vanished away.

Moreover, it must be kept in mind that when the prophet complains that the outcome does not correspond with the promise, or is not what the promise led the chosen people to expect, he does not, for that reason, charge God with falsehood. Instead, he brings forward this apparent discrepancy for another purpose: to encourage himself, by considering the Divine promises, to approach the throne of grace with greater confidence and boldness.

And, while he urged this difficulty before God, he was fully persuaded that God would inevitably show Himself faithful to His word.

Just as most people internalize their sorrow and keep it to themselves because they despair of deriving any benefit from prayer, so true believers, the more frankly and familiarly they appeal to God concerning His promises, the more valiantly do they wrestle against their distrust and encourage themselves in the hope of a favorable outcome.