God Changed Saul's Heart

Saul is an interesting case study in the role God plays in our faith. 1 Samuel 10:9 says "God changed Saul's heart." Verse 10 says "the Spirit of God came upon him in power, and he joined them in prophesying." We can note this was obviously not of Saul's doing. Apparently he wasn't rejecting it either. By the end of Saul's life this dramatically changes. I don't intend to draw any conclusions yet, just point this out as one more example to possibly help us better understand the mystery of the doctrine of election (Romans 9).