There came a messenger unto Saul— Thus, by the timely interposition of Providence, David was delivered from one of the most immediate dangers of his life: and from this time they called the place המחלקות סלע Selang hammachlekoth; i.e. the rock of divisions: the rock where Saul was obliged to divide himself from David, and go after the Philistines. Osiander thinks that David gave it this name in gratitude for his deliverance, as a memorial that there God had, by little less than a miracle, divided his enemy from him. Possibly this was a rock of one of those mountains which Solomon calls the mountains of Bether, (Song of Solomon 2:17.) in the Margin of our Bible interpreted division.
Note; (1.) God has various ways of delivering his people; even the Philistines shall sometimes be made instruments of his mercy to them. (2.) They who have fled to the mountain of refuge Jesus Christ, shall find such a strong rock of division between them and danger, that none shall be able to hurt them.