There were yards for sheep and goats at that place, near a cave. David and his men were in that place before Saul and his men got there, and David’s mob went into the cave to hide. Later on, Saul and his men came, and Saul went into the cave by himself to go to the toilet. But David and his men were already in that cave, right at the back. The cave was very big, so Saul did not see them.