What does 1 Chronicles 12:18 mean?

Then the Spirit came over Amasai, the leader of the Thirty, and he said, 'We're with you, David! We're on your side, son of Jesse! Peace to you, and peace to those who help you, because your God is with you.' So David welcomed them and made them leaders in his army. 1 Chronicles 12:18 - Modern Text Bible

(Amasai, inspired by God's Spirit, declared their loyalty to David. This reassurance convinced David to trust them and give them responsibility.)