For you remember, brothers, our labor and travail; for working night and day, that we might not burden any of you, we preached to you the Gospel of God.

 (i) He speaks of Satan blocking his way when he desired to come to Thessalonica. The word he uses (egkoptein, G1465) is the technical word for putting up a road-block calculated to stop an expedition on the march. It is Satan's work to throw obstacles into the Christian's way--and it is our work to surmount them. 