On earth there is always a battle raging between God and those who oppose Him and fight against Him. God fights not by Himself directly but through His servants who have been sent by Him. This was the situation in Jeremiah’s time. God sent His army — a young man named Jeremiah — to fight against those who opposed Him. Jeremiah was equipped by God to such an extent that he became a fortified city and an iron pillar and brass walls. Because God was with him to deliver him, the opposers would not prevail over him (v. 19).