The truth is that this verse, though presented as if it were promoting OT Law-based righteousness, it is not, as Paul tells us that all of that is dung. Of course it is the righteousness of Christ that Paul is teaching, not the righteousness of the law.You are making your opinion to be above God's AND Paul's...who you clearly twist the words of.
But notice what Paul says about righteousness and the Old Testament.
2 Tim.3:16] All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: [17] That the man of God may be perfect, thoroughly furnished unto all good works.
Philippians 3
6 Concerning zeal, persecuting the church; touching the righteousness which is in the law, blameless.
7 But what things were gain to me, those I counted loss for Christ.
8 Yea doubtless, and I count all things but loss for the excellency of the knowledge of Christ Jesus my Lord: for whom I have suffered the loss of all things, and do count them but dung, that I may win Christ,
9 And be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith:
2 Peter 3
14 Wherefore, beloved, seeing that ye look for such things, be diligent that ye may be found of him in peace, without spot, and blameless.
15 And account that the longsuffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you;
16 As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction.