No man could keep the letter of the law. "Thou shall surely die"
The word "keep" must be defined.
I remember once for a long period sharing with another person who used the word "keep" in a way that opposed the gospel.
No man could keep any commandment coming from God who is not a man.
To "keep" is to guard closely with all of ones new heart, soul and mind. We can keep in that way because he empowers us living in these bodies of death who keep his laws imperfectly. He is the perfect One.
As the just one(letter of the law) and the justifier (law of faith) He is one who kept the law perfectly. We therefore can keep his commandments as he works in us with us. . His loving commandments forgive as well as show error . Without his perfect law we would have no way to hear Him and seek after when we do violate it denying him if and when do .
With Him there is forgiveness without. . . .the letter of the law death
Romans 3:26 To declare, I say, at this time
his righteousness: that
he might be
just, and the
justifier of
him which
believeth in
Jesus.