John Calvin Commentary Philemon 1:22

"But withal prepare me also a lodging: for I hope that through your prayers I shall be granted unto you." — Philemon 1:22 (ASV)

But at the same time prepare for me a lodging. This confidence must have powerfully excited and moved Philemon; and next, he offers him the hope of being gratified by his own arrival. Although we do not know whether Paul was later released from prison, this statement is not absurd, even if he was disappointed in the hope he cherished about God’s temporal kindness. He had no confident hope of his release, except as it pleased God. Accordingly, he always kept his mind in suspense until the will of God was made known by the result.

That through your prayers I shall be given to you. Here it deserves notice that he says that everything believers obtain through their prayers, is given to them; for from this we infer that our prayers, though they are not unsuccessful, yet have no power through their own merit, for what is yielded to them is of free grace.