Focusing our thoughts on Christ instead of on our sins opens the door to our hearts and makes it possible for him to reach inside and remove the compulsions and desires for evil. Only when our attention is focused in the right place can he give us a new heart and nature. When Christ holds your attention, he will at last hold your heart and be able to make you free.
Steven A. Cramer, "Armed With Righteousness"
The saying "what holds your attention, holds you" is not just a group of words that make a coherent sentence when put in the correct order. No, there is legitimate and profound truth behind this phrase.
We all have thoughts enter into our mind. We all do, by intentionally thinking those thoughts or Satan putting them there to trip us up. And some are positive, some aren't. But....whether we choose to entertain those thoughts, is our decision. We have control over that.
What holds our attention, holds us!
So, what do we do if Satan is relentless? For one, we need to stop putting ourselves into situations or circumstances where he is present and can be relentless in the first place. And we stop watching shows or movies where the Spirit leaves. We stop heeding social media. We stop listening to inappropriate music. We stop doing whatever makes the Spirit leave, along with His divine protection.
Then, we can focus on paying attention to what really matters in the eternal scheme. Then will Christ be there to cleanse our mind and give us a new heart.
That's how it is done. But, it's not always easy to do it that way. It'll take extreme effort and sacrifice on our part. "A broken heart and a contrite spirit". Humility is key.