Denying the 'old' self (taking up its cross) and following Jesus

One thing we can ascertain from the Apostle Paul's writings, is that when he says he kept doing the things that he didn't want to do, even into his old age, we'll never be completely set free from the influences of the 'old man' self. Some call it our egoic nature. Some call it our 'human condition'. The Catholic church calls it 'concupiscence'. The question remains: why doesn't God just completely remove the influences of our sinful nature, or, 'old man' self? Theologians over the centuries have attempted to answer this mysterious question. But, all they can do is speculate. No one knows the exact answer. Like Job, Abraham, Solomon, and other Biblical faithful, it comes down to a conscious 'Faith' decision. A faith/belief that some how, some way, God is in sovereign control of 'all things' and is causing all things to work together for a believer's good. We walk by faith, and not by sight, as sacred scripture states. So, while we keep striving for holiness, we don't beat ourselves up when our bodies do the things that we don't want it to do at times. For like the Apostle Paul, as a new creation/identity in Christ, it's not our 'new/true self' that sins, it's the remnants of the 'old/false man self' that does. So, we're never, ever condemned.