Not that he feared them, or could not as easily have conquered them, as he did the whole host of the Philistines; but because he would be free from all obligation or temptation of doing them any harm, though it were in his own just and necessary defence.
Related Commentaries of Judges 15:12
Judges 15:12
12 And they said unto him, We are come down to bind thee, that we may deliver thee into the hand of the Philistines. And Samson said unto them, Swear unto me, that ye will not fall upon me yourselves.