1 Samuel 21:10

David arose and fed to Achish A miserable condition, to be forced to flee to those for protection who were naturally his bitter enemies. For this was the city of Goliath whom he had slain, and whose sword he had now about him. But it must be considered that Saul's rage was so great, and his power and diligence also in hunting after him, that he despaired of escaping any other way; and a desperate disease requireth a desperate remedy. Perhaps indeed he thought he should not be known: or, being now in disgrace with Saul, he thought the Philistines might take him for Saul's enemy, and so receive him gladly. The king elect is here an exile: anointed to the crown, and yet forced to run his country! So do God's providences sometimes run counter to his promises, for the trial of our faith, and the glorifying of his name in accomplishing his counsels, notwithstanding the difficulties which lie in the way.