Paul makes this request seven times in his epistles. He knew that the success of the minister depended largely on the prayers of God’s people.
Some congregations seem to be pervaded largely by a heavenly atmosphere. You feel its hallowed influence the moment you enter the house. It matters not how rich may be the tones of a bell; if it be struck in vacuo or under water, you get no sound, or only a heavy thud; strike it in the air and how mellow its notes ring out.
So with preaching in or out of the atmosphere of devotion. A praying people make a strong pulpit. A Paul may plant and an Apollos may water, but it is God who gives the increase, and He gives it only in answer to prayer.