Sometimes a person wonders, "for how long will I have to fight this? I thought I had already made a lot of progress, but suddenly I see that I'm again struggling with the yetzer hara in the same old ways". A person must realize that the yetzer hara never gives up. Every day he instigates a new fight, in all types of creative ways. But keep hope! Nothing we have accomplished in the past is lost, but G-d wants us to keep going to higher and higher levels. This wouldn't be possible if we made progress once and simply finished. So each day the yetzer hara tries again, in new ways, or, in the same old ways that we had thought we were finished with already. But we must learn from the yetzer hara, and also never give up. We need to strengthen ourselves every day anew. And this is precisely what G-d wants from us.