If you are not obeying His laws than you are not obeying His Spirit. The letter is still required because its still a sin to lie or steal or vain His name, or worship idols, not keep His Sabbath holy etc. the difference with the New Covenant is our obedience is out of our love, not because its a commandment. We will know which spirit we are following through our actions and choices. God does not make those choices for us, which is why we are told to be doers, not hearers said by James while under the New Covenant
James 1:22 But be doers of the word, and not hearers only, deceiving yourselves .
This question was asked to Jesus in the New Covenant and He replied:
Mathew 19:17 So He said to him, “Why do you call Me good? No one
is good but One,
that is, God. But if you want to enter into life,
keep the commandments.” (its an action)
I think we can go around and around. If the Spirit is leading you to not sin and keeping all of God's commandments that's great, its what we all should strive for, but if you sin, that spirit is not led by God and I do not think its wise to think that it is, we still have to make choices, and God's Spirit wants us to keep His commandments because obedience is how we show God our love.
John 14:15-18
"If you love Me, keep My commandments. And I will pray the Father, and He will give you another Helper, that He may abide with you forever— the Spirit of truth, whom
the world cannot receive, because it neither sees Him nor knows Him; but you know Him, for He dwells with you and will be in you. I will not leave you orphans; I will come to you.
1 John 5:3 For this is the love of God, that we keep His commandments. And His commandments are not burdensome.
John 15:10 Jesus said If ye keep my commandments, ye shall abide in my love; even as I have kept my Father's commandments, and abide in his love.