The reason for secrecy is not clear. It will come up again at the end of the narrative when Saul refuses to tell his uncle what Samuel said to him (1 Samuel 10:14–16). Possibly it is to prevent rumours from spreading too soon, rumours that could influence the final selection process and acceptance of Saul’s kingship (see 1 Samuel 10:17 – 11:15).
27 As they were going down to the outskirts of the city, Samuel said to Saul, “Tell the servant to pass on before us, and when he has passed on, stop here yourself for a while, that I may make known to you the word of God.”