The law of the spirit of life: what is that?
This is Christ Jesus living in us by His Holy Spirit, and His leading us by His peace, by God's grace:
"Let not sin therefore reign in your mortal body, that ye should obey it in the lusts thereof. 13Neither yield ye your members as instruments of unrighteousness unto sin: but yield yourselves unto God, as those that are alive from the dead, and your members as instruments of righteousness unto God. 14For sin shall not have dominion over you: for ye are not under the law, but under grace." (Romans 6: 12-14)
The grace of God not only pays for all our sins (all of them, eternally), but allows us to receive eternal life, Christ in us, the hope of glory (Colossians 1: 27)
"4Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit unto God. 5For when we were in the flesh, the motions of sins, which were by the law, did work in our members to bring forth fruit unto death. 6But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not in the oldness of the letter." (Romans 7: 4-6)
The blood of Jesus cleanses us of all sin (1 John 1: 7), and His Spirit now lives and flows in us:
"20But ye have an unction from the Holy One, and ye know all things." (1 John 2: 20)
"27But the anointing which ye have received of him abideth in you, and ye need not that any man teach you: but as the same anointing teacheth you of all things, and is truth, and is no lie, and even as it hath taught you, ye shall abide in him." (1 John 2: 27)
This direction operates based on His peace:
"And let the peace of God rule in your hearts, to the which also ye are called in one body; and be ye thankful." (Colossians 3: 15)
We no longer meditate on the Ten Commandments, because Jesus fulfilled them at the Cross (Matthew 5: 17; Hebrews 8: 10-13). We meditate on the Gospel, that in Christ we are justified from all things that we could not receive through the law of Moses (Acts 13: 38-39)
We meditate on the grace of God, revealed to us in Jesus' death on the Cross, and manifested through His resurrection and ministry as our High Priest:
"11For the grace of God that bringeth salvation hath appeared to all men, 12Teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly, in this present world; 13Looking for that blessed hope, and the glorious appearing of the great God and our Saviour Jesus Christ; 14Who gave himself for us, that he might redeem us from all iniquity, and purify unto himself a peculiar people, zealous of good works." (Titus 2: 11-14)
That is what the law of faith is all about today, under the New Covenant. We receive the grace of God and His gift of righteousness every day (Romans 5: 15-17), and He causes us to reign in life, His life.