1 Samuel 19:20 - Joseph Benson’s Commentary on the Old and New Testaments

Saul sent messengers to take David His implacable hatred had abolished all respect and reverence for Samuel, (under whose protection David now was,) and for the college of the prophets, which was a kind of sanctuary to those that fled to it. Samuel standing as appointed over them To instruct and direct them in their holy exercises. For though they prophesied by divine inspiration, yet they were both to prepare themselves for it beforehand, and to make good improvement of it afterward, in both which they needed Samuel's counsel and assistance. And whereas some might falsely pretend to those raptures, or the devil might transform himself into an angel of light, Samuel's presence and judgment were necessary to prevent and to detect such impostures. Besides, Samuel would, by his present conjunction with them in those holy exercises, encourage them, and stir up others to the coveting of those gifts, and to the performance of such religious duties. The Spirit of God was upon the messengers of Saul That, being rapt up into an ecstasy, and no longer masters of themselves, their minds might be wholly taken off from their design of seizing David. They prophesied Praised God in hymns, by a sudden impulse, which they could not resist.