People who are led by the Spirit are not in some moral vacuum:
Galatians 5:16-18
16 I say then: Walk in the Spirit, and you shall not fulfill the lust of the flesh. 17 For the flesh lusts against the Spirit, and the Spirit against the flesh; and these are contrary to one another, so that you do not do the things that you wish.
18 But if you are led by the Spirit, you are not under the law.
Hebrews 7:18-19
18 For on the one hand, the former commandment is set aside because of its weakness and uselessness 19 (for the law made nothing perfect); but on the other hand, a better hope is introduced, through which we draw near to God.
I say why abide in what is weak and useless and makes nothing perfect? Why would you want to do that when a better hope has been introduced - and that through that which is better we draw near to God?
Hebrews 8:6-7
6 But as it is, Christ has obtained a ministry that is as much more excellent than the old as the covenant he mediates is better, since it is enacted on better promises. 7 For if that first covenant had been faultless, there would have been no occasion to look for a second.
How did that work out for them?
Who's saying that we just follow our fleshly desires? Perhaps you have not read the folks' posts on Grace . . . no one here is saying that.
And are you asserting that the New Covenant Scriptures are not inspired? That Jesus did not mean it when He said,
John 16:12-15
12 “I still have many things to say to you, but you cannot bear them now. 13 When the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come. 14 He will glorify me, for he will take what is mine and declare it to you. 15 All that the Father has is mine; therefore I said that he will take what is mine and declare it to you.
And that the following is not true?
Galatians 5:16-18
16 I say then: Walk in the Spirit, and you shall not fulfill the lust of the flesh. 17 For the flesh lusts against the Spirit, and the Spirit against the flesh; and these are contrary to one another, so that you do not do the things that you wish.
18 But if you are led by the Spirit, you are not under the law.
All Scripture is good for instruction (2 Tim. 3:16), however that does not mean that those in Christ are bound to Old Covenant Law. And the way you typed the above is very misleading - no one here is saying to cancel out all that God has taught - that's NOT what Grace folk are saying at all. Was the Old Covenant cancelled as a functioning covenantal system? You bet - as is proven by the destruction of the Temple and the establishing of Christ as the Perfect and Forever High Priest - The Old Covenant has NO priesthood. The New Covenant is clearly in place, setting the Old aside as Hebrews 7:18-19 says above. As for the Scripture that tells us to cancel out the Old Covenant, for those in Christ, yep - the Law is cancelled, we have died to it, we have been released from it (Col. 2:13-15, Rom. 7:4-6, Ephesians 2:14-16).
-JGIG