Rom 7:19-20 For the good that I will to do, I do not do; but the evil I will not to do, that I practice. Now if I do what I will not to do, it is no longer I who do it, but sin that dwells in me.

You go around and around the parking lot trying to find a close place to park.
Finally, a car pulls out right at the entrance.
You make a turn down that row and just before you get to the parking space a little car whips into the space.
It is very aggravating and easy to have sinful thoughts or let something awful slip from your lips.
You didn’t want to think it.
You didn’t want to say it.
You didn’t want to shout at the person indicating what kind of idiot they were.
It’s just one example of the many things that can happen to upset your Christianity during a day.
It takes discipline to keep from thinking bad thoughts, saying awful things, or doing stupid acts.
Paul understood this when he wrote in Romans 7.
Like you, he wanted to do good but he did not.
He did not want to do evil but did it anyway.
He realized that sin will always conflict and fight against the spiritual nature of Christianity.
To overcome it you need the help of the Holy Spirit but it also takes a conscientious effort on your part too, that is, discipline.