Halakhah к Шмот 15:3

Halakhah, as it applies to Jews, recognizes that man has no right to make war against his fellow. Standard translations of the Bible render Exodus 15:3 as "The Lord is a man of war; the Lord is His name." Rashi, citing similar usages having the same connotation, renders the Hebrew term "ish" as "master." Thus the translation should read, "The Lord is the master of war; the Lord is His name." God is described as the master of war because only He may grant dispensation to engage in warfare. The very name of the Lord signifies that He alone exercises dominion over the universe. Only God as the Creator of mankind and proprietor of all life may grant permission for the taking of the lives of His creatures.