Albert Barnes Commentary 1 Samuel 10:6

"and the Spirit of Jehovah will come mightily upon thee, and thou shalt prophesy with them, and shalt be turned into another man." — 1 Samuel 10:6 (ASV)

Will come upon you - The word translated as “come” means to “come” or “pass upon,” like fire breaking out and spreading (Amos 5:6). Therefore, it is frequently used to describe the Spirit of God coming upon someone (Judges 15:14; 1 Samuel 10:10; 1 Samuel 11:6; 1 Samuel 16:13).

You shall be turned into another man - This is a remarkable expression that occurs nowhere else in Scripture. It describes the change in mental power and energy that would result from the outpouring of the Spirit of the Lord (1 Samuel 10:9). In Samson's case, this meant supernatural physical strength. In Saul's case, it was a capacity for ruling and leading the people—a capacity he previously lacked—which the Spirit worked in him (Isaiah 11:2–4).