מדרש אויף שמות 14:14

"the L–rd will war for you": Not only now, but He will always war for you against your enemies.

When Israel do His will, He wars for them, viz. (Exodus 14:14) "The L–rd will war for you." And when they do not do His will, He wars against them, viz. (Isaiah 63:10) "And He turned into a foe of theirs; He warred against them."

“I have likened you [dimitikh], my love,” Rabbi Eliezer said: [This is analogous] to a princess who was taken captive and her father was about to redeem her. She was motioning to her captors and saying to them: ‘I am for you, I am yours, and I will follow you.’²⁵⁰She said this out of fear of what they might do to her if her father was unable to redeem her. Her father said to her: ‘Do you believe that I do not have the wherewithal to redeem you? I am silencing you [duma dimitikh], be silent.’ So too, when the Israelites were encamped at the sea: “Egypt pursued them and overtook them encamped by the sea” (Exodus 14:9). The Israelites, in their fear, were motioning to the Egyptians and saying to them: ‘We are for you, we are yours, and we will follow you.’ The Holy One blessed be He said to them: ‘Do you believe that I do not have the wherewithal to redeem you? I am silencing you [duma dimitikh], I have silenced you.’ That is what is written: “The Lord will wage war for you and you shall be silent” (Exodus 14:14).