Sometimes we are like a David, standing up alone against a great and powerful Goliath. The holy Jewish soul that wants to serve Hashem, is pitted against the powerful Yetzer Hara who seems so much stronger than us. It can look like there is no way to win this battle, in the same way that that there was no way David could vanquish the mighty Goliath. But he did. He did, because he came with Bitachon - Trust in G-d. He did, because he came in the name of the Lord. If only we could see how our little actions affect all the upper worlds... If only we could see what pleasure we give Hashem when we try to serve him even though he seems so hidden from us... If only we could know how our daily battles affect our eternity and that of all of Klal Yisrael... We must believe this even though we don't see it. All Hashem truly wants from us in this world is "Emunah". All the other Mitzvos are just a means to that end. As Chaza"l said; "The prophet Chavakuk put all the Mitzvos into one Mitzva - "Tzaddik Be'emunaso Yichyeh" - "A Tzadik will live in his Faith". Fight the Yetzer Hara. Tell him, like David told Goliath, that although he is stronger, we are coming to fight him in the name of the Lord.
Just sling some stones of Teffilah and Emunah at him and he will fall with a mighty thud!