20Then Saul sent messengers to take David, and when they saw the company of the prophets prophesying, and Samuel standing as head over them, the Spirit of God came upon the messengers of Saul, and they also prophesied.
The Spirit of God caused the men sent by Saul to prophesy.1 Confusing them and rendering them helpless, the Spirit, in an extraordinary way, protected David from capture.2
20 Then Saul sent messengers to take David, and when they saw the company of the prophets prophesying, and Samuel standing as head over them, the Spirit of God came upon the messengers of Saul, and they also prophesied.