What does it mean for people to believe and turn to the Lord?
Acts 11:21 (ESV)
21And the hand of the Lord was with them, and a great number who believed turned to the Lord.
For people to believe and turn to the Lord means that people embraced the message which they heard and submitted to the teaching of Jesus, as they received it from those who proclaimed him to them.
21 And the hand of the Lord was with them, and a great number who believed turned to the Lord.