This is the germination stage. The scattering of gospel seed has occurred (19-20) and now the gospel has given new birth. New birth does not occur without the hand of God. As 1 Cor 3:6 says, "I planted, Apollos watered, but God gave the growth."
What does it mean that a great number who believed turned to the Lord? Don't these happen at the same time? Yes, they do. The phrase is literally, "Having trusted, they turned upon the Lord." These actions occur simultaneously. They are both active verbs in the same past tense. One cannot be genuine if separated from the other. True belief in Christ means full belief and rest on Him.
"Turned TO the Lord" actually means turned upon the Lord, stressing their utter dependence on Jesus as their Master. They placed themselves fully on Him signifying their true faith and dismissal of their own merits for salvation. The Gospel so accentuates Christ, that all other existence recognizes its dependence on Him. "And He is before all things, and in Him all things hold together" (Col 1:17). Here, turning does not focus on what is now behind us, but what is newly ahead of us.
Antioch was ranked third in population during this time, behind only Rome and Alexandria. The city was known for numerous mystery cults and pagan religious diversity. However, its religious diversity tolerated God-fearers. Christians arrived with the message of Christ crucified and risen, and people believed, turning from their Jewish religion as they recognized the Messiah had come or turning from their pagan idolatry to the Savior "not made by human hands" (Acts 19:26).
Notice in this verse, the clarity of these initial moments of belief for the new Christians. They understood the message, and their full-on response by turning to Christ rather than simply believing. The question, "How little can I do and still be saved?" is strikingly absent in this verse because true repentance is full belief conjoined with changed mind, heart, soul, and strength.
Discipleship emerges from a clearly planted message. Watering down (limiting the water poured on the seed planted) will produce a quickly withering plant that can only hope to remain a sapling. Towering trees grow from the healthiest of seeds sown. The Lord's hand nurtures these well-planted seeds, and the shoot emerges.
But discipleship does not stop here...