Defeating the Yeitzer Hara With Emunah

Defeating the Yeitzer Hara With Emunah:
The Ahavas Shalom explains this pasuk as follows:
“When you go out to war on your enemy.” This is referring to when a person readies himself to fight a war against his true enemy, the yeitzer hara. One should not think the yeitzer hara is too strong to defeat in every battle. Rather, he should believe that he can always be “on his enemy”, meaning that he can end up on top of him if he tries hard enough to overcome. The more emunah one has that he can win this war, the more victorious he will be and “Hashem will give him over in your hands...”

We see from this that the main way to beat the yeitzer hara is through having bitachon that Hashem will help you defeat him.