“Ok, I really don't want to start a debate or anything, just an answer and I'll return to my supposedly “evil” catholic ways. If everything is completely predestined then after one is "saved" what is the purpose of asking God for something in prayer? If everything is predestined should God not already know our need and whims? Another question...why the creation of evil, or the need for a final battle?”
Now I love questions like these, whether they come via cyberspace, from a coworker, or a relative. These are opportunities not only to answer with kindness, but also to point to answers found in the Bible rather than in the teaching magisterium of the Roman Catholic Church. With Roman Catholics, the emphasis in the discussion should gravitate on the ultimate authority of Scripture. A Roman Catholic believes that God has spoken in the Bible, so the answers should provoke them to read the Bible.
Church history is replete with debate over predestination and God's sovereignty. Think of it this way: great struggles with particular aspects of the Christian faith are well worth the effort. Sometimes we need to wrestle with God.
You ask, “If everything is completely predestined then after one is "saved" what is the purpose of asking God for something in prayer?” The first and foremost reason a Christian must pray is the Bible commands us to do so. 1 Thessalonians 5:17 tells Christians to pray continually. Ephesians 6:18 states, "And pray in the Spirit on all occasions". There is deep mystery in prayer- how could there not be? The finite human is speaking to the infinite God of the universe. Whether or not we can understand the relationship between how our prayers and an infinite God who knows everything “works” does not alleviate a Christian from the Biblical exhortation to pray.
You ask, “If everything is predestined should God not already know our need and whims?” Indeed, God does know everything; even Roman Catholic theology admits this. God, because He is omniscient, must know everything. If He didn't, He wouldn't be God. Remember what the Lord Jesus said in Matthew 6:8: "Your Father knows what you need before you ask him." Here we come face to face with a deep mystery of God. The Bible tells us That God knows our needs beforehand. This is a great comfort to a Christian. The God of the Bible is not caught off-guard by anything that occurs in this world.
You ask, “why the creation of evil, or the need for a final battle?” Again, there is deep mystery in the existence of evil. There is no totally satisfactory answer this side of heaven that explains completely how a sovereign all-good God and evil both exist. But we do have some knowledge revealed to us from the pages of the Bible that explain the existence of evil. We know, that ultimately all of reality and the universe culminate in God's glory as Revelation 22 describes. Romans 8:28 states "We know that in all things God works for the good..." in describing the life of a Christian. After going through a myriad of "evil" circumstances Joseph declares to his brothers in Genesis 50, "You intended to harm me, but God intended it for good to accomplish what is now being done, the saving of many lives." So, in all circumstances, the evil that occurs happens for a reason: God uses it for a good purpose. Even the worst event in all human history was predetermined by God: Christ was handed over to wicked men by God's set purpose (Acts 2:23). What was the most evil act committed in human history is used by God for the most glorious act in human history: the redemption of the world.
Well, how did this Catholic respond? She stated, “Thank you for the responses, they cleared some things up, I am very surprised at the kindness, I am very curious about Calvinism but I usually am met with anger and rudeness, this was a nice change.”
It is possible to tell people the truth in love. My prayer for this woman is that the answers provoke her to search the pages of Scripture rather than the official teachings of the Roman Catholic Church. These answers only scratch the surface, highlighting my own “wrestling” with the Bible. I am Calvinist because of the Biblical text: It says what it says. I may not understand all of the Biblical mysteries totally, but to be obedient to God I believe what is revealed. I respect anyone who grapples with these types of questions. I have had many friends who have hated the type of answers I gave, only to hear them tell me years later that what they once hated became the sweetest of all comfort.