John Calvin Commentary Psalms 119:90

"Thy faithfulness is unto all generations: Thou hast established the earth, and it abideth." — Psalms 119:90 (ASV)

Thy truth is from generation to generation. In this verse, the Psalmist repeats and confirms the same sentiment. He expressly teaches that although the faithful live for a short time as strangers on earth and soon pass away, yet their life is not perishable, since they are begotten again of an incorruptible seed.

He, however, proceeds still further. He had previously instructed us to pierce by faith into heaven, because we will find nothing in the world on which we can assuredly rest; and now he again teaches us, by experience, that although the world is subject to revolutions, yet bright and significant testimonies to the truth of God shine forth in it, so that the steadfastness of His word is not exclusively confined to heaven but comes down even to us who dwell on the earth.

For this reason, it is added that the earth continues steadfast, just as it was established by God at the beginning. Lord, as if it had been said, even on the earth we see Your truth reflected as it were in a mirror; for though it is suspended in the midst of the sea, yet it continues to remain in the same state.

These two things, then, are quite consistent: first, that the steadfastness of God’s word is not to be judged according to the condition of the world, which is always fluctuating and fades away as a shadow; and secondly, that people are yet ungrateful if they do not acknowledge the constancy that in many respects marks the framework of the world.

For the earth, which otherwise could not occupy the position it does for a single moment, nevertheless abides steadfast because God’s word is the foundation on which it rests. Furthermore, no one has any ground for objecting that it is a hard thing to go beyond this world in search of the evidences of God’s truth, since, in that case, it would be too remote from human apprehension. The prophet meets this objection by affirming that although God’s truth dwells in heaven, we may yet see conspicuous proofs of it at our very feet, which may gradually advance us to as perfect a knowledge of it as our limited capacity will permit.

Thus the prophet, on the one hand, exhorts us to rise above the whole world by faith, so that the word of God may be found by experience to be adequate, as it really is adequate, to sustain our faith; and, on the other hand, he warns us that we have no excuse if, by the very sight of the earth, we do not discover the truth of God, since legible traces of it are to be found at our feet.

In the first clause, people are called back from the vanity of their own understanding; and, in the other, their weakness is relieved, so that they may have a foretaste on earth of what is to be found more fully in heaven.