Is "Ha-Mim, they shall not be helped" a correct supplication that the Messenger of Allah, peace and blessings be upon him, used to invoke against the enemies?

"Ha Mim La Yunsarun" (حم لا ينصرون) was a slogan used by Muslims in some battles for identification, and not a supplication to invoke victory. The meaning of the slogan is a distinctive sign among fighters, especially in the dark. Muslims adopted other slogans as well. "Ha Mim La Yunsarun" are few words that carry optimism about the defeat of enemies; they are a statement of fact, not a supplication.