"Saul sent men to David's house to watch it and to kill him in the morning. But Michal, David's wife, warned him, "If you don't run for your life tonight, tomorrow you'll be killed." (1 Samuel 19:11)
"When David had fled and made his escape, he went to Samuel at Ramah and told him all that Saul had done to him. Then he and Samuel went to Naioth and stayed there. Word came to Saul: "David is in Naioth at Ramah"; so he sent men to capture him. But when they saw a group of prophets prophesying, with Samuel standing there as their leader, the Spirit of God came upon Saul's men and they also prophesied. Saul was told about it, and he sent more men, and they prophesied too. Saul sent men a third time, and they also prophesied. Finally, he himself left for Ramah and went to the great cistern at Secu. And he asked, "Where are Samuel and David?"
"Over in Naioth at Ramah," they said. So Saul went to Naioth at Ramah. But the Spirit of God came even upon him, and he walked along prophesying until he came to Naioth. He stripped off his robes and also prophesied in Samuel's presence. He lay that way all that day and night. This is why people say, "Is Saul also among the prophets?" (1 Samuel 19:18-24)
This is amazing. Saul's men come after David to kill him. God temporarily turns would-be killers into prophets. So Saul then sends more men to kill David. God turns them as well. A third time Saul sends men to kill David, and God turns them into prophets too. Finally, Saul basically decides, "If you want something done right, do it yourself," and he comes to finish the job himself. But God even turns Saul into a prophet, long enough for David to escape. Saul was so overwhelmed by the power of the Spirit of God that he was prevented from carrying out his intention to take David's life, to the point of laying down in one place all day and all night.
This shows that God does indeed intervene in human affairs. It also shows that God does not allow human free will to reign supreme. In fact, it shows that the power of the Spirit of God is irresistible. God turned enemies into servants. He magnified His power over the spirits of men. God, in His sovereignty, for the purpose of insuring that His will is accomplished, and to glorify Himself, many times changes people, or causes them to do things that they would otherwise never do. Instead of seizing David, Saul and his men were seized by the power of the Holy Spirit. In similar manner, God also causes those who are lost, unsaved, under His wrath and His enemies to repent and turn their lives over to Him, whereupon He regenerates them (makes them into brand new creatures); washes away their past, present and future sins; legally credits them with the holiness of Christ; and then, being that they are now holy and clean vessels fit for God to dwell in, they become living tabernacles as the Holy Spirit then indwells them, and, like an engagement ring, serves as a sign guaranteeing that they will be part of the bride of Christ (the invisible, universal Church). Of course, this was not the case with Saul and his men, because this was the time before the promised Messiah, when God had promised that He would turn hearts of stone into hearts of flesh. Therefore, the Holy Spirit only indwelled Saul and his men temporarily, and they were not regenerated.
Another thing this shows is that, when you trust in God, He is able to protect you. In fleeing to Samuel, David made God his refuge. While in Saul's court, Saul had already tried to pin David to the wall with his spear twice. So, even though David was in the palace of the king, the most powerful man in the land, David found little rest or satisfaction. However, when he joined with Samuel and the prophets, who were serving God, he found fellowship, safety and the greatest relief imaginable to him in his present distress.