'Enemy' in the Bible

And if thy people Israel be smitten down before the enemy, because they have sinned against thee, and shall turn again and confess thy name, and pray and make supplication before thee in this house;

If they sin against thee (for there is no man that sinneth not), and thou be angry with them, and deliver them to the enemy, so that they carry them away captive unto a land far off or near;

But if thou wilt go, do valiantly , be strong for the battle: God will cast thee down before the enemy; for God hath power to help, and to cast down.

And under their hand was an army, three hundred thousand and seven thousand and five hundred, that made war with mighty power, to help the king against the enemy.