Since Purgatory is only taught in Roman Catholic doctrine, that will be the source to define the concept. The Catechism of the Catholic Church teaches “All who die in God's grace, but still imperfectly purified, are indeed assured of their eternal salvation; but after death they undergo purification, so as to achieve the holiness necessary to enter the joy of heaven.”
The Apostle Paul tells us about eternal salvation. Romans 8:1-4 says, “There is therefore now no condemnation for those who are in Christ Jesus. For the law of the Spirit of life in Christ Jesus has set you free from the law of sin and of death …who do not walk according to the flesh, but according to the Spirit.”
We do not go to heaven by being good, as we imperfect people are unable to be good enough (Romans 7:22-24). Jesus' sacrifice is enough, and he died once…for all (Hebrews 10:10). The scriptures speak of two classes that are saved. 1Timothy 4:10 "…God, who is the Savior of all men, especially of believers."
"All men" (everyone – Acts 24:15) will come back to the earth, which will be perfected, and they will then learn of God's ways."Believers" have been called by God. The believer will delight to "deny himself, and take up his cross, and follow" Jesus (Matthew 16:24, Psalm 40:8). These live as he lived (to the best of their ability) and will be resurrected as he is…in heaven (Romans 8:17). It is these believers who are purified in this life. Our purification through discipline and suffering is for the purpose of developing a mature, Christlike character. (Hebrew 12:3-11)
The Scriptures also do not support a concept of suffering after death to purify anyone from their sins. When a person dies, the scriptures teach “the dead know nothing, and they have no more reward,…there is no work, nor device, nor knowledge, nor wisdom, in the grave, whither thou goest.” Ecclesiastes 9:5,10. Jesus likened death to sleep (John 11:11-13). Since the dead know nothing, they cannot suffer or be purified. Our only rescue from the sleep of death is in the resurrection. “Marvel not at this for the hour is coming in which all that are in their graves shall come forth…” John 5:28,29. It is when Jesus is reigning and awakens mankind from death, that men will learn righteousness and be restored to the perfection lost when Adam sinned. Jeremiah 31:33,34, “I will put my law in their inward parts, and write it in their hearts…they shall be my people. And they shall teach no more every man his neighbor…saying, Know the LORD: for they shall all know me, from the least of them unto the greatest…I will forgive their iniquity, and I will remember their sin no more.” (Also Isaiah 11:9, Revelation 21:4)