John Calvin Commentary 2 Corinthians 8:9

"For ye know the grace of our Lord Jesus Christ, that, though he was rich, yet for your sakes he became poor, that ye through his poverty might become rich." — 2 Corinthians 8:9 (ASV)

For you know the grace. Having mentioned love, he presents Christ as an absolutely perfect and unique pattern of it. “Though he was rich,” he says, “he resigned the possession of all blessings, that he might enrich us by his poverty.” He does not afterward state for what purpose he mentions this, but leaves it for them to consider; for no one can fail to perceive that by this example we are stirred up to beneficence, so that we may not hold back when help is to be given to our brothers.

Christ was rich, because He was God, under whose power and authority all things are; and further, even in our human nature, which He put on, as the Apostle testifies (Hebrews 1:2; Hebrews 2:8), He was the heir of all things, since He was placed by His Father over all creatures, and all things were placed under His feet. Nevertheless, He became poor, because He refrained from His possessions and thus gave up His right for a time. We see what destitution and extreme poverty in all things awaited Him immediately upon His birth. We hear what He Himself says (Luke 9:58):

The foxes have holes, and the birds of the air have nests: the Son of man hath not where to lay his head.

Therefore, He has consecrated poverty in His own person, so that believers may no longer regard it with horror. By His poverty He has enriched us all for this purpose—that we may not find it hard to take from our abundance what we may spend on our brothers.