Scripture says first He was chosen by the revered judge and prophet Samuel, under the direction of God.
The people would have voted anyone in front of them but it was God who put the person (Saul) before them to vote for.
forgive the colloquial language here but I do see some humor in the exchange regarding choice and nuh no choice
Samuel went over to Jesse's and had Jesse proudly present all his tall good looking boys but Samuel was not convinced. he said: you don't have anymore boys? I need more boys.
well, there is that day dreaming David back in the fields somewhere. but he smells like sheep
Samuels face lit up. yeah. I want to see him and don't dawdle cause we are not eating until I see him
Jesse gave a sigh of oy vey and sent for David. David came in smiling and was the picture of health and good looking to boot. Just not in the way the other boys were.
Samuel knew that David was the one God had sent him to annoint. So David felt the oil of God's anointing pouring down over his head and from day on, David, who was already close to God, knew God in a different way; knew things would now be different