John Calvin Commentary 1 Corinthians 8:3

"but if any man loveth God, the same is known by him." — 1 Corinthians 8:3 (ASV)

But if any man loves God, here we have the conclusion, in which he shows what is especially commendable in Christians. It even makes knowledge and all other gifts commendable if we love God; for if this is the case, we will also love our neighbors in Him. In this way, all our actions will be properly regulated and consequently approved by God. He shows, therefore, by its results, that no learning is commendable that is not dipped in the love of God, because that alone ensures that whatever gifts we have are approved by Him, as it is said in the second Epistle—

If any man be in Christ he is a new creature (2 Corinthians 5:17).

By this he implies that without the Spirit of regeneration, everything else, regardless of its outward appearance, has no value. To be known by God means to be esteemed, or to be counted among His sons. Thus, He erases all proud persons from the book of life (Philippians 4:3) and from the list of the devout.