In a lecture that Rabbi Reuven wolf gives at Maayon Yisrael, he mentions what it means in Tehillim 27, the verse, "Hashem you are my light and salvation." He mentions about the challenge we have with fighting our yetzer hara, and how it can be very powerful over us.
I know this personally. I use to have such a big temper, but found that it only made things worse. I decided to do something about it. It's hard when you are in the moment and feel so much tension, but we just need to remember to try to clear our mind and breath. It's a continuous test, but we have the ability to choose the better path.
Rabbi Wolf explains that this is meant by the verse 'Hashem is my light and salvation.' Eventhough we have a strong desire to do something we shouldn't do, we can turn it around and choose another way with Hashem's help
Here is a video from another verse in Tehillim 27