2 Pet. 1.1: “obtained a like precious faith with us in the righteousness of our God and the Saviour Jesus Christ…”
This echoes Paul’s words in Phi. 3 – 9 and be found in him, not having a righteousness of mine own, even that which is of the law, but that which is through faith in Christ, the righteousness which is from God by faith…
and Romans 3:
21 But now apart from the law a righteousness of God hath been manifested, being witnessed by the law and the prophets; 22 even the righteousness of God through faith in Jesus Christ unto all them that believe; for there is no distinction; 23 for all have sinned, and fall short of the glory of God; 24 being justified freely by his grace through the redemption that is in Christ Jesus:25 whom God set forth to be a propitiation, through faith, in his blood, to show his righteousness because of the passing over of the sins done aforetime, in the forbearance of God; 26 for the showing, I say, of his righteousness at this present season: that he might himself be just, and the justifier of him that hath faith in Jesus. 27 Where then is the glorying? It is excluded. By what manner of law? of works? Nay: but by a law of faith. 28 We reckon therefore that a man is justified by faith apart from the works of the law.;
[Note that Paul makes a distinction between law and works, so as to exclude any kind of works belonging to us when it comes to our justification, even our salvation. "Where then is the glorying? It is excluded." This is supported by Eph. 2:8-9, for by grace have ye been saved through faith; and that not of yourselves, it is the gift of God; not of works, that no man should glory.]
This understanding, that man is justified by faith apart works is easily understood as the same with which Peter is writing as he opens his epistle. The admonitions to godly living that follow have the same thrust one finds elsewhere. We are saved by the righteousness of God that comes by faith for the very purpose of righteousness as evidenced by godly living, i.e. the fruit of the Spirit that Peter mentions. Being justified through faith alone doesn’t render these admonitions empty. Rather, because we are still sinners we need the Word of God in the imperative to convict us, sober us and direct us, that through faith and repentance we might more earnestly cling to Christ only, who died for our sins (being aware of how far we continually fall short) that we might live more faithfully unto God.
9 For he that lacketh these things is blind, seeing only what is near, having forgotten the cleansing from his old sins. 10 Wherefore, brethren, give the more diligence to make your calling and election sure: for if ye do these things, ye shall never stumble:
As to “the blind”… these can be understood as the hypocrites, those who outwardly profess, but inwardly have no true faith in Christ. They have forgotten the cleansing of sin promised in their baptism in that their repentance wasn’t accompanied by faith. And Peter’s warning, if heeded, might yet result yet in true faith for these.
And overall, by attending to the things Peter admonishes, a believer will be all the more sure of God’s gracious call and election, not as an additional cause securing that salvation, but evidence affirming God’s gratuitous and free mercy, by the working of the Holy Spirit, through faith.