"22Seeing ye have purified your souls in obeying the truth through the Spirit unto unfeigned love of the brethren, see that ye love one another with a pure heart fervently: 23Being born again, not of corruptible seed, but of incorruptible, by the word of God, which liveth and abideth for ever." (1 Peter 1: 22-23)
In religion, man strives to purify himself through what He does.
The truth is, it is the truth which purifies our souls.
The Gospel speaks of our righteousness before God because of Jesus:
"Be it known unto you therefore, men and brethren, that through this man is preached unto you the forgiveness of sins: 39And by him all that believe are justified from all things, from which ye could not be justified by the law of Moses." (Acts 13: 38-39)
We are not justified through the law of Moses, or anything else that we do, but what Jesus did:
"For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him." (2 Corinthians 5: 21)
The focus of the Gospel is that we are born again, taken out of dead Adam, and brought to life in Christ Jesus (Colossians 3: 1-4)
Now, when Peter writes about obeying the truth, He is not talking doing something, but believing that Jesus is our justification:
"In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise," (Ephesians 1: 13)
"Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified." (Galatians 2: 16)
We do not purify ourselves, but rather we rest in the truth that Jesus has purified us, and in fact:
"1Behold, what manner of love the Father hath bestowed upon us, that we should be called the sons of God: therefore the world knoweth us not, because it knew him not. 2Beloved, now are we the sons of God, and it doth not yet appear what we shall be: but we know that, when he shall appear, we shall be like him; for we shall see him as he is. 3And every man that hath this hope in him purifieth himself, even as he is pure." (1 John 3: 1-3)
Yet, James tells us to purify our hearts, does he not?
"Draw nigh to God, and he will draw nigh to you. Cleanse your hands, ye sinners; and purify your hearts, ye double minded" (James 4: 8)
Let us remember the importance of rightly dividing the Word of Truth (2 Timothy 2: 15). James is writing to his Jewish brethren, in which some of them believed on Jesus, and some did not. In the Fourth chapter of his letter, James is writing to those who do not believe, yet.
Because we believe on Him, we can rest assured that we are purified from all sin, and even when we sin, the blood of Jesus cleanses us (1 John 1: 7)
The Gospel purifies us, and when we believe it, we can rest assured that we have been purified, and do not have to do something more.