Charles Spurgeon Commentary Colossians 4:3-4

"withal praying for us also, that God may open unto us a door for the word, to speak the mystery of Christ, for which I am also in bonds; that I may make it manifest, as I ought to speak." — Colossians 4:3-4 (ASV)

Withal praying also for us, that God would open unto us a door of utterance, to speak the mystery of Christ, for which I am also in bonds: that I may make it manifest, as I ought to speak.

So the preacher of the gospel asks your prayers: and it is a part of the duties arising out of the relationship between Christians that those who are taught should pray for those who teach God's Word.