The Philistines gathered their armies together - Sir Isaac Newton conjectures that the Philistines had got a great increase to their armies by vast numbers of men which Amasis had driven out of Egypt. This, with Samuel’s death, and David’s disgrace, were no inconsiderable motives to a new war, front which the Philistines had now every thing to hope.
Thou shalt go out with me to battle - This he said, being deceived by what David had told him.