How do I stay pure one day at a time?
You have to have a sense of perfection. This does not mean you're going to be perfect in regard to the temptations of lust. It is a desire for a 24 hour perfection: to keep yourself pure from masturbation. You go into the supermarket, you see a woman dressed immodestly, yes, you're going to be drawn to that. You may fall and have a second look, a thought may pop into your head.
But you want to be quick to cut it off. Lust is always going to be coming at you, but you want to do nothing with it. Don't feed it by engaging in the fantasy and then the masturbation. Twenty four hours without masturbation is completely doable, and you can continue to do it by staying vigilant. That is key. Then intensity. St Joseph the Hesychast battled the temptation of lust severely, and they say for eight years he was the absolute model and pinnacle of intensity.
He was fully engaged in the fight. He knew that every single day the devil was going to hit him with temptations, and every day he was ready to suit up and engage in the battle. I see men who are passive, who try to go with the flow. Those guys get taken out super easily, because their heart is not in it. You have to come with as much ferocity and intensity as the devil is coming at you.
The devil wants to destroy you, and you have to have the sense that it's kill or be killed: you will not settle for being destroyed. Even if you fall in battle, you get up and say, I am going to press forward, tomorrow is a new day, and I'm going 100 percent tomorrow. Every day has to be approached in this manner.

