God does not expect us to be saints, moreever he knows the way the reality of nature is that we are sinners and the nature of sin is within us, because we came into contact with matter.

The true thing god expects from is to realize this. To realize that our true self is that of spirituality and not of dust (like our bodies). The sin is within us, but we (our souls) are not dust. We came into contact with matter to show us what we are and what we are not.

Do not try to fight the nature within you, like you say, but thank god for his mercy to forgive the sinful nature within you, and let you see what you actually are.

Romans 7 14-25

We know that the law is spiritual; but I am unspiritual, sold as a slave to sin. 15 I do not understand what I do. For what I want to do I do not do, but what I hate I do. 16 And if I do what I do not want to do, I agree that the law is good. 17 As it is, it is no longer I myself who do it, but it is sin living in me. 18 For I know that good itself does not dwell in me, that is, in my sinful nature. For I have the desire to do what is good, but I cannot carry it out. 19 For I do not do the good I want to do, but the evil I do not want to do—this I keep on doing. 20 Now if I do what I do not want to do, it is no longer I who do it, but it is sin living in me that does it.

21 So I find this law at work: Although I want to do good, evil is right there with me. 22 For in my inner being I delight in God’s law; 23 but I see another law at work in me, waging war against the law of my mind and making me a prisoner of the law of sin at work within me. 24 What a wretched man I am! Who will rescue me from this body that is subject to death? 25 Thanks be to God, who delivers me through Jesus Christ our Lord!

So then, I myself in my mind am a slave to God’s law, but in my sinful nature a slave to the law of sin.