And Jonathan climbed up upon his hands and upon his feet, and his armourbearer after him: and they fell before Jonathan; and his armourbearer slew after him. Jonathan climbed up - It seems he had a part of the rock still to get over. When he got over he began to slay the guards, which were about twenty in number, these were of a sort of outpost or advanced guard to the garrison.
Slew after him - Jonathan knocked them down, and the armor-bearer despatched them. This seems to be the meaning.