Colossians 4:3-4
At the same time, pray also for us, that God may open to us a door for the word, to declare the mystery of Christ, on account of which I am in prison— that I may make it clear, which is how I ought to speak.

How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching?
Romans 10:14