Source: http://www.ewtn.com/library/ANSWERS/TULIP.HTMFurther,from the same article by James Akin,he cites Thomas Aquinas from the Catholic side,"...Aquinas declared that special grace is necessary for man to do any supernaturally good act, to love God, to fulfill God's commandments, to gain eternal life, to prepare for salvation, to rise from sin, to avoid sin, and to persevere
Calvinists claim God predestines people by choosing which individuals will accept his offer of salvation. These people are known as "the elect" . They are not saved against their will. It is because God has chosen them that they will desire to come to him in the first place. Those who are not among the elect, "the reprobate," will not desire to come to God, will not do so, and thus will not be saved
Akin clarifies,"Although a Catholic may agree with unconditional election, he may not affirm "double-predestination," a doctrine Calvinists often infer from it. This teaching claims that in addition to electing some people to salvation God also sends others to damnation.A Catholic would say God sends no one to damnation. You can't go to hell unless you choose to and you only make it to heaven through God's grace.
Finally,Akin writes,"A Catholic also may say that, in going to the cross, Christ intended to make salvation possible for all men, but he did not intend to make salvation actual for all men--otherwise we would have to say that Christ went to the cross intending that all men would end up in heaven." To put it another way Jesus died on the cross so that all men could be saved,but not that all men WOULD be saved.
As for the doctrine of irresistible grace grace,Akin notes: Catholics must say that, while God may give efficacious grace only to some, he gives sufficient grace to all. This is presupposed by the fact that he intended the atonement to be sufficient for all. Vatican II stated, "[S]ince Christ died for all men, and since the ultimate calling of man is in fact one and divine, we ought to believe that the Holy Spirit in a manner known only to God offers to every man the possibility of being associated with this paschal mystery." God created Adam and Eve in innocence yet tempted they failed to trust and disobeyed.
The final point in Akin's article is perseverance of the saints and that claims(like osas)no matter what trials they face, they will always persevere, so their salvation is eternally secure.Here Catholics and Calvinists really part company. We would call it perseverance meaning you keep on until the end...but that you have to get there first. You have no way of knowing future behavior based on present. The Catholic Church doesn't canonize saints until the end and even at that there are rigorous guidelines that have to be followed.BTW. The Catholic Church doesn't create saints.God does. Canonization doesn't make one a saint.PERIOD. God already does that-we simply give God's work recognition. They are,the saints,in our family aka as the COMMUNION of saints.
Where does purgatory fit into all this? First let's see what the Catechism has to say about the doctrine:III. THE FINAL PURIFICATION, OR PURGATORY
1030 All who die in God's grace and friendship, 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.
1031 The Church gives the name Purgatory to this final purification of the elect, which is entirely different from the punishment of the damned.606 The Church formulated her doctrine of faith on Purgatory especially at the Councils of Florence and Trent. The tradition of the Church, by reference to certain texts of Scripture, speaks of a cleansing fire:607
As for certain lesser faults, we must believe that, before the Final Judgment, there is a purifying fire. He who is truth says that whoever utters blasphemy against the Holy Spirit will be pardoned neither in this age nor in the age to come. From this sentence we understand that certain offenses can be forgiven in this age, but certain others in the age to come.608 1032 This teaching is also based on the practice of prayer for the dead, already mentioned in Sacred Scripture: "Therefore [Judas Maccabeus] made atonement for the dead, that they might be delivered from their sin."609 From the beginning the Church has honored the memory of the dead and offered prayers in suffrage for them, above all the Eucharistic sacrifice, so that, thus purified, they may attain the beatific vision of God.610 The Church also commends almsgiving, indulgences, and works of penance undertaken on behalf of the dead:
Let us help and commemorate them. If Job's sons were purified by their father's sacrifice, why would we doubt that our offerings for the dead bring them some consolation? Let us not hesitate to help those who have died and to offer our prayers for them.611
That's it.Not much more.
It's a good thing because scripture tells us,in Revelation 21:27 "nothing unclean shall enter heaven." Unless we leave this earth perfectly ready for the beatific vision purgatory makes sense.Who would want to be with the love of their life-God-with even a little taint of imperfection anyway.We would want to meet God totally purified.
The Catechism explains,
1024 This perfect life with the Most Holy Trinity — this communion of life and love with the Trinity, with the Virgin Mary, the angels and all the blessed — is called “heaven.” Heaven is the ultimate end and fulfillment of the deepest human longings, the state of supreme, definitive happiness.
Purgatory is just further proof of the mercy of God.He wants us to be in heaven.