How long are you going to mourn: See study note on 1 Samuel 15:35.
Bethlehem is about five miles south of Jerusalem. It later became known as the City of David (Luke 2:11) and is the birthplace of Jesus.
Jesse was the grandson of Boaz and Ruth (Ruth 4:22).
I have selected: This Hebrew verb means God saw one of Jesse's sons and chose him based on what he saw. God, the eternal king, knows better than the people of Israel how to choose a good king to serve the nation. He provided a replacement for Saul who would lead Israel well.