John Calvin Commentary Philippians 1:19

"For I know that this shall turn out to my salvation, through your supplication and the supply of the Spirit of Jesus Christ," — Philippians 1:19 (ASV)

For I know that. As some published the gospel with the intention of making Paul hateful, so that they might stir up against him even more the rage of his enemies, he tells them beforehand that their wicked attempts will do him no harm, because the Lord will turn them to an opposite purpose. “Though they plot my destruction,” he says, “yet I trust that all their attempts will have no other effect than Christ being glorified in me—which is a most beneficial thing for me.”

For it is evident from what follows that he is not speaking of the safety of his body. But what is the source of this confidence on Paul's part? It is from what he teaches elsewhere (Romans 8:28)—that all things contribute to the advantage of God’s true worshipers, even though the whole world, with the devil, its prince, should conspire for their ruin.

Through your prayer. So that he may stir them up to pray more fervently, he declares that he is confident that the Lord will give them an answer to their prayers. Nor does he use pretense, for he who depends for help on the prayers of the saints relies on the promise of God. Meanwhile, nothing is taken away from the unmerited goodness of God, on which our prayers, and what is obtained through them, depend.

And the supply. Let us not suppose that, because he joins these two things in one connection, they are consequently alike. The statement must, therefore, be explained in this manner: “I know that all this will turn out for my advantage, through the provision of the Spirit, with you also helping through prayer.” Thus, the supply of the Spirit is the efficient cause, while prayer is a subordinate help. We must also observe the specific meaning of the Greek term, for ἐπιχορηγία is used to mean the furnishing of what is lacking, just as the Spirit of God pours into us everything of which we are destitute.

He also calls Him the Spirit of Jesus Christ, to indicate that if we are Christians, this Spirit is common to all of us, inasmuch as the Spirit was poured upon Christ with all fullness, so that Christ, according to the measure of His grace, might distribute to each of His members, as is fitting.