Fulfilled in us the righteousness of the law !
Rom 8:3-4
3 For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh:
4 That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.
For all men who were blessed to have Christ as their Surety, when He lived and died in their stead, the righteousness of the law was fulfilled in them. This is by imputation, all of the moral requirements of righteousness due unto God by man, to be summed up here Matt 22:37-39
37 Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind.
38 This is the first and great commandment.
39 And the second is like unto it, Thou shalt love thy neighbour as thyself.
40 On these two commandments hang all the law and the prophets.
Paul wrote in Rom 13:8-10
8 Owe no man any thing, but to love one another: for he that loveth another hath fulfilled the law.
9 For this, Thou shalt not commit adultery, Thou shalt not kill, Thou shalt not steal, Thou shalt not bear false witness, Thou shalt not covet; and if there be any other commandment, it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself.
10 Love worketh no ill to his neighbour: therefore love is the fulfilling of the law.
The Life and death of Christ has fulfilled this love required to the law.
Rom 5:19
19 For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous.
Christ's obedience to the Law of God, both active and passive is imputed to all for whom He lived and died. So He being their surety savior is the end of the law for righteousness to eveyone that believeth. He as their surety is also the author of their believing, for they first believed in and by Him, His obedience to the Law for them was also by Faith, because without Faith its impossible to please God Heb 11:6 which Christ did please God as our surety here on earth , rendering complete obedience to Gods law ! Isa 42:21
21 The Lord is well pleased for his righteousness' sake; he will magnify the law, and make it honourable.