Verses 17 through 27 give an account of how Saul was made king by Samuel.
Samuel gathered the people together to Jehovah at Mizpah (v. 17). This indicates that Saul was made king by Samuel before, in the sight of, the people of Israel.
Saul was made king by the casting of lots to prove that he was chosen by God (vv. 20-23a). Saul was chosen by lot, but he was hiding himself among the baggage, and the people could not find him. But Jehovah told them where he was hiding, and they took him from there.
Samuel then showed Saul's person to the people (vv. 23b-24). Concerning Saul, who was taller than all the people from his shoulders and up, Samuel said, "See him whom Jehovah has chosen, that there is none like him among all the people" (v. 24a). All the people shouted and said, "Long live the king!"
According to verse 25a, Samuel told the people the custom of the kingdom. He wrote it in a book and laid it before Jehovah.
Saul went to his house at Gibeah, and the men of valor, whose hearts God had touched, went with him (v. 26). This was the issue of Saul's being made king by Samuel.
Some worthless men said, "How can this man save us?" They despised him and brought him no present (v. 27). Whereas the others brought presents to celebrate Saul's kingship, these worthless men refused to participate in the celebration. But Saul kept silent.
Saul, the son of Kish, had gone to search for the lost donkeys and he returned to his father with the kingship. Regarding this, Samuel cooperated with God for His eternal kingdom, that is, for the eternal economy of God.