Actually it contradicts nothing in the NT, and fits perfectly with what the Jews believed and what the Christians (Paul, for example) taught, in both OT and NT: that is 1) that a man can be punished for sin after he is forgiven (2Sam 12:13-14); that there is a place or process by which the spirits of just men are made perfect (Heb 12:22-23); that there is a place where a saved man, after he has died , can suffer loss as through fire (1Cor 3:13-15); and that nothing unclean shall enter Heaven (Rev 21:27). Straight from the Scriptures we see the principles of the doctrine on “purgatory” (or whatever you may want to call it).
Okay… well, firstly the 1st. Samuel 12 passage is taken out of it’s context. Purgatory deals with eternity. 1st. Samuel doesn’t at all. I agree to a sowing and reaping process understood here in this temporal world, but there is no doctrine addressing eternity’s issues in 1s. Sam.
Secondly is the Hebrew 12 passage which is in a allegory form about our spiritual Mt. Zion. The reference is clarified in verse 28 to be the kingdom of God that cannot be shaken. Sanctified=perfect believers will rule this kingdom on that great day.
Thirdly the 1st. Cor. 3 passage is a reference to the judgment seat of Christ where all believers will stand and give an account for their works to God. This judgment is not a judgment over sin but of works. The sin judgment has passed, see John 5:24. It is our works that will come under the metaphorical fires of testing to reveal the quality of our work. A reward, or relinquishment of reward, will be offered at that time. Verse 12 shows, again in a metaphor context, 6 qualities of works represented by what is listed in that verse. Gold, Silver, precious stones, wood, hey, straw. All to be tested by fire.
Your reference to Rev. 21:27 is all true. "nothing unclean will ever enter it… but only those who are written in the Lambs book of life slain from the foundation of the world. Rev. 13:8. If you have received Jesus Christ as savior, Christ wrote your name in His book before the world began.
But in none of these passages you offer, do we even show a hint of the concept of purgatory. You would think that such an important fate as purgatory, there would be very detailed and repetitive information about it. Nope. not at all my friend.