John Calvin Commentary Psalms 18:49

"Therefore I will give thanks unto thee, O Jehovah, among the nations, And will sing praises unto thy name." — Psalms 18:49 (ASV)

Therefore will I praise thee, O Jehovah! In this verse, he teaches us that the blessings God had conferred upon him, of which he had spoken, are worthy of being celebrated with extraordinary and unusual praises, so that the fame of them might reach even the Gentiles. There is in the words an implied contrast between the ordinary worship of God, which the faithful were then accustomed to perform in the temple, and this thanksgiving of which David speaks, which could not be confined within such narrow limits.

The meaning, therefore, is: O Lord, I will not only give you thanks in the assembly of your people, according to the ritual which you have appointed in your law, but your praises shall extend to a greater distance, even as your grace towards me is worthy of being recounted throughout the whole world.

Moreover, from these words, we conclude that this passage contains a prophecy concerning the kingdom of Christ, which was to come. Unless the Gentiles had been drawn into the fellowship of the chosen people and united into one body with them, to praise God among them would have been to sing his praises among the deaf—which would have been a foolish task and wasted effort. Accordingly, Paul very properly and suitably proves from this text that the calling of the Gentiles was not something that happened by chance or haphazardly (Romans 15:9).

We will later see in many places that the Church is appointed to be the sacred dwelling-place for proclaiming the praises of God. And, therefore, the name of God could not have been rightly and profitably celebrated outside Judea until the ears of the Gentiles were opened, which occurred when God adopted them and called them to Himself by the gospel.