'Single' in the Bible

This will be a confirming sign for you that will be fulfilled through your two sons, Hophni and Phinehas: in a single day they both will die!

But the army said to Saul, "Should Jonathan, who won this great victory in Israel, die? May it never be! As surely as the Lord lives, not a single hair of his head will fall to the ground! For it is with the help of God that he has acted today." So the army rescued Jonathan from death.

Who has the king of Israel come out after? Who is it that you are pursuing? A dead dog? A single flea?