As David was delivered from the snares of Saul, John Knox deduces in his interpretation of 1 Samuel 19:1-7, so will God protect his followers from those who seek them harm. Indeed, Knox even goes so far in his Treatise on Prayer as to give a personal example, speaking of God delivering him from his own times of difficulty and despair.
1 Samuel 19:1-7
Saul told his son Jonathan and all the attendants to kill David. But Jonathan had taken a great liking to David and warned him, “My father Saul is looking for a chance to kill you. Be on your guard tomorrow morning; go into hiding and stay there. I will go out and stand with my father in the field where you are. I’ll speak to him about you and will tell you what I find out.” Jonathan spoke well of David to Saul his father and said to him, “Let not the king do wrong to his servant David; he has not wronged you, and what he has done has benefited you greatly. He took his life in his hands when he killed the Philistine. The Lord won a great victory for all Israel, and you saw it and were glad. Why then would you do wrong to an innocent man like David by killing him for no reason?” Saul listened to Jonathan and took this oath: “As surely as the Lord lives, David will not be put to death.” So Jonathan called David and told him the whole conversation. He brought him to Saul, and David was with Saul as before.
Commentary on 1 Samuel 19:1-7
The notion that God delivers his chosen from their enemies is not written for David only, but for all those who shall suffer tribulation, until the end of the world. For I, John Knox—let this be said to the acclaim and praise of God alone—in anguish of mind and vehement tribulation and affliction, called on the Lord when not only the ungodly but even my faithful brothers (even my own self, that is, my natural understanding) judged my case to be irremediable. And yet, in my greatest calamity, and when my pains were most cruel, God’s eternal wisdom willed that my hands should be a writer, far contrary to the judgment of carnal reason, which his mercy has proved true, blessed be his holy name. And therefore I dare to be bold in the truth of God’s Word to promise that—notwithstanding the vehemence of trouble, the long continuance of it, the despair of all people and the fearfulness, danger, pain and anguish of our own hearts—yet if we call constantly to God, even beyond all human expectation, he shall deliver.
1-2 Samuel, 1-2 Kings, 1-2 Chronicles, eds. Derek Cooper and Martin J. Lohrmann, Reformation Commentary on Scripture, OT vol. 5, p. 95.