I wouldn't be would I? Mystery Grace is nonsense and Kingom Fullness is futurist and therefore wrong.
No, the expression is not in Paul nor in how he thinks. Prove otherwise.
Not surprisingly, you conclude from what you have already shunned going in as being two false positives, that such is the case with the other of those three you also view as falsehood.
Not surprising, given the "one size fits all" approach your over reliance on external sources along with your own over the Scripture, has left you with.
The following is...
The Righteousness of the Law By Faith
Romans 2:21 Thou therefore which teachest another, teachest thou not thyself? thou that preachest a man should not steal, dost thou steal? 2:22 Thou that sayest a man should not commit adultery, dost thou commit adultery? thou that abhorrest idols, dost thou commit sacrilege? 2:23 Thou that makest thy boast of the law, through breaking the law dishonourest thou God? 2:24 For the name of God is blasphemed among the Gentiles through you, as it is written. 2:25 For circumcision verily profiteth, if thou keep the law: but if thou be a breaker of the law, thy circumcision is made uncircumcision.
They were to keep the law.
But not merely keep it outwardly, but inwardly, from the heart, or by faith.
2:28 For he is not a Jew, which is one outwardly; neither is that circumcision, which is outward in the flesh: 2:29 But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.
Romans 9:31 But Israel, which followed after the law of righteousness, hath not attained to the law of righteousness. 9:32 Wherefore? Because they sought it not by faith, but as it were by the works of the law. For they stumbled at that stumblingstone; 9:33 As it is written, Behold, I lay in Sion a stumblingstone and rock of offence: and whosoever believeth on him shall not be ashamed.
Had they kept the law by faith; had they actually believed it, and not merely professed it outwardly, they would have believed the Law's testimony that Jesus was the Christ.
They were walking the walk, talking the talk, but inwardly, they were in unbelief - whited sepulcre, pew warmers.
John 5:38 And ye have not his word abiding in you: for whom he hath sent, him ye believe not. 5:39 Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me. 5:40 And ye will not come to me, that ye might have life. 5:41 I receive not honour from men. 5:42 But I know you, that ye have not the love of God in you. 5:43 I am come in my Father's name, and ye receive me not: if another shall come in his own name, him ye will receive. 5:44 How can ye believe, which receive honour one of another, and seek not the honour that cometh from God only? 5:45 Do not think that I will accuse you to the Father: there is one that accuseth you, even Moses, in whom ye trust. 5:46 For had ye believed Moses, ye would have believed me: for he wrote of me. 5:47 But if ye believe not his writings, how shall ye believe my words?
In contrast to...
Luke 1:5 There was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth. 1:6 And they were both righteous before God, walking in all the commandments and ordinances of the Lord blameless.
And...
John 1:40 One of the two which heard John speak, and followed him, was Andrew, Simon Peter's brother. 1:41 He first findeth his own brother Simon, and saith unto him, We have found the Messias, which is, being interpreted, the Christ. 1:45 Philip findeth Nathanael, and saith unto him, We have found him, of whom Moses in the law, and the prophets, did write, Jesus of Nazareth, the son of Joseph. 1:49 Nathanael answered and saith unto him, Rabbi, thou art the Son of God; thou art the King of Israel.
While, in contrast to that again...
Acts 7:51 Ye stiffnecked and uncircumcised in heart and ears, ye do always resist the Holy Ghost: as your fathers did, so do ye. 7:52 Which of the prophets have not your fathers persecuted? and they have slain them which shewed before of the coming of the Just One; of whom ye have been now the betrayers and murderers: 7:53 Who have received the law by the disposition of angels, and have not kept it.
There...
...is your requested proof...
Gainsay it all you want.
In contrast...
2 Corinthians 4:13 We having the same spirit of faith, according as it is written, I believed, and therefore have I spoken; we also believe, and therefore speak;
