1 Samuel 14:6-10

And Jonathan said to the young man that bare his armor, Come, and let us go over unto the garrison of these uncircumcised: it may be that Jehovah will work for us; for there is no restraint to Jehovah to save by many or by few. And his armorbearer said unto him, Do all that is in thy heart: turn thee, behold, I am with thee according to thy heart. Then said Jonathan, Behold, we will pass over unto the men, and we will disclose ourselves unto them. If they say thus unto us, Tarry until we come to you; then we will stand still in our place, and will not go up unto them. But if they say thus, Come up unto us; then we will go up; for Jehovah hath delivered them into our hand: and this shall be the sign unto us.