John Calvin Commentary Philippians 4:6

"In nothing be anxious; but in everything by prayer and supplication with thanksgiving let your requests be made known unto God." — Philippians 4:6 (ASV)

But in all things—Paul uses the singular number here, but in the neuter gender; the expression, therefore, is equivalent to omni negotio, (in every matter,) for (prayer) and (supplication) are feminine nouns. In these words he exhorts the Philippians, as David does all the godly in Psalm 55:22, and Peter also in 1 Peter 5:7, to cast all their care upon the Lord. For we are not made of iron, so as not to be shaken by temptations. But this is our consolation, this is our solace—to deposit, or (to speak more accurately) to disburden into the bosom of God everything that harasses us. Confidence, it is true, brings tranquility to our minds, but only if we exercise ourselves in prayer. Whenever, therefore, we are assailed by any temptation, let us immediately turn to prayer, as to a sacred refuge.

The term requests he uses here to denote desires or wishes. He wants us to make these known to God by prayer and supplication, as though believers pour out their hearts before God when they commit themselves and all that they have to Him. Those, indeed, who look here and there to the vain comforts of the world may appear to be somewhat relieved; but there is one sure refuge—leaning upon the Lord.

With thanksgiving. Since many often pray to God wrongly, full of complaints or murmurings, as though they had good reason to accuse Him, while others cannot tolerate delay if He does not immediately gratify their desires, Paul for this reason combines thanksgiving with prayers. It is as if he had said that we should desire from the Lord the things necessary for us in such a way that we nevertheless submit our own desires to His good pleasure, and give thanks while presenting petitions. And, unquestionably, gratitude will have this effect on us—that the will of God will be the main substance of our desires.