World evangelization was the plan that Jesus shared with His apostles (1:8). At 13:1 it was the time to execute such a plan.
We observe from the text that it was not Saul or the church, but the Holy Spirit who took the initiative of this new venture (13:2).
It was God’s plan, and it was God’s work. The missionaries were to be His instruments in the work (cf. 14:26–27).
Irving L. Jensen, Jensen’s Survey of the New Testament: Search and Discover (Chicago: Moody Press, 1981).