The Law of God is Spiritual.

Rom 7:14  For we know that the law is spiritual: but I am carnal, sold under sin. 

The law is spiritual, is it any wonder when we know this…

Joh_4:24  God is a Spirit: and they that worship him must worship him in spirit and in truth.

That God's law is spiritual makes a lot of sense. This is why you could keep the letter of the law perfectly and still NOT be God's. Because it must be kept SPIRITUALLY as well as physically, and mentally. We must worship God in SPIRIT and TRUTH.

The law is spiritual, could God give us a moral law that wasn't spiritual, abled to be completely comprehended spiritually?

We fail to follow the law because we are carnal, embracing our carnal natures. We are sold under sin. Truthfully we were born with the carnal nature we possess and sin is right there- a drawing away from God and a propensity towards self, towards serving our flesh natures. I'm not sure we can remember our first realized sin, but most of us probably have some idea of the 'mischief' we got up to as children. We can likely recall moments of pure selfishness, of anger towards others because we didn't get our way. Maybe you can recall various sinful moments of your life because oftentimes some of our more sinful moments are written on our minds permanently. We serve self so much, in so many ways above and beyond any consideration for others or God.  We are truly sold under sin, carnal. Recognizing ourselves in this way makes it possible for us to comprehend our most desperate need to be saved by the Sinless One, the only One who can save us from ourselves.

Rom 7:15  For that which I do I allow not: for what I would, that do I not; but what I hate, that do I. 

Rom 7:16  If then I do that which I would not, I consent unto the law that it is good. 

When we recognize the wrong inside us we are automatically agreeing that the moral law is a good thing. You can't understand that you are wrong without there being a right, it's impossible.

Rom 7:17  Now then it is no more I that do it, but sin that dwelleth in me. 

Rom 7:18  For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not. 

How incredibly true this is. I have gone to this passage so many times in my life because I agonize over my failure to do that which is good. This carnal nature WARS against the SPIRITUAL nature.

Rom 7:19  For the good that I would I do not: but the evil which I would not, that I do. 

Rom 7:20  Now if I do that I would not, it is no more I that do it, but sin that dwelleth in me. 

Rom 7:21  I find then a law, that, when I would do good, evil is present with me. 

Rom 7:22  For I delight in the law of God after the inward man: 

Rom 7:23  But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members. 

Law of God- in us, our spirit with His Spirit.

Another law in our bodies-warring with the law of our minds- held captive to the law of sin in our bodies.

Rom 7:24  O wretched man that I am! who shall deliver me from the body of this death? 

Our bodies captive to the law of sin, WHO will deliver us from our bodies which consent to the law of sin?

Rom 7:25  I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin. 

We use our minds to SERVE the law of God, we CHOOSE to serve the spiritual law with our spirit.  We make a conscious choice to serve the law of God and when the law of sin in our flesh rears its ugly head, we seek forgiveness, repenting- endlessly.

Through JESUS CHRIST OUR LORD alone are we delivered from our bodies, from the law of sin in our bodies.

All by His amazing grace, love, mercy!!!!!!