the young men: In ancient times, enemy armies sometimes picked individuals or small groups to fight as representative gladiators. This practice is often called champion warfare (see also 1 Samuel 17).
compete: The Hebrew term usually suggests an element of play. A contest of champions might have been seen as a high-stakes game. In this case, it resolved nothing. The fighting grew into a much larger battle with more casualties (2 Samuel 2:17–32).