Predestination is controversial because it clashes with a humanistic exaltation of the individual. It is a hard doctrine to understand. The doctrine is serious, but it shouldn't cause divisions. It is is the assertion that God is in control. Predestination is God in control of tomorrow.
God is in control over sin. God pre-ordained that Joseph's wicked brothers should sell him into slavery (Gen. 50:20). There were two intentions at work in Joseph's story. The brothers' intentions toward Joseph were evil, but God's intention was good. God did not cause the brothers to sin, but He allowed their sin for a purpose.
God hardened wicked Pharaoh's heart (Ex. 4:21). God's intention was to create an opportunity for God to glorify His own name (Ex. 7). God wasn't being whimsical, or mean. Pharaoh already was an unbeliever. God allowed that wicked man's wicked heart to run unchecked.
Joseph confidently predicted that God would bring them back to the promised land, and his descendents would carry Joseph's bones back with them (Gen. 50:24-25). Joseph was confident because he knew God alone would bring it about. Jesus said that nothing is impossible with God. God does not depend on nature, circumstances, or human beings.
God often acts with unilateral authority. God unilaterally ordained Moses to be His prophet (Ex. 3:10). God did the same thing to Jeremiah (Jer. 1:4-5). Christ unilaterally chose Saul to see Him and become an apostle (Acts 22:14). Paul said God set him apart from his mother's womb to be an apostle (Galatians 1:15).
God's hand holds the reins of the world empires. God raised up the Assyrians (Isaiah 10:5-7). God similarly raised up the Babylonians (Habakkuk 1:5-6), then God raised up the Medes against the Babylonians (Jeremiah 51:11). Daniel predicted a succession of empires (Babylon, Medo-Persia, Greek, Roman). God was in control of it all.
God even rules over Satan! Read Job 1-2 -- Satan could do no more to Job than what God ordained. Satan helped bring about Christ's crucifixion, by possessing Judas (Luke 22:3). But Peter later says that all the bad actors in Christ's death did what God had predetermined (Acts 2:23, 4:28). God doesn't make people evil, but He knows how to exploit evil people for His own good purposes.
People have problems with the doctrine of predestination for a number of reasons. The liberal person naturally hates the doctrine, because it nullifies human supremacy. But Christians have also disputed over predestination for generations. Some will say:
"The doctrine wipes out free will." My answer is that the humanistic view of free-will (the people are completely autonomous) isn't in the Bible. The Bible teaches that people have free-will, but it also says that God's power extends over everything. The Lord doesn't cause every choice, but He can steer people when he needs to do so. The Lord struck Israel's enemies' minds with terror (Judges 7:22), causing them to attack each other. God sent an evil spirit to drive rebellious Saul crazy (1 Samuel 16:14). God caused the chief eunuch to favor Daniel (Daniel 1:9), and caused King Artaxerxes to favor Nehemiah (Nehemiah 2:1-8). God's hands are never tied. The will seeks what it wants to do, but the Lord's plan is always what comes out in the end.
"Predestination means we're not responsible for what we do!" No, not really. Notice how the Bible says we have no spiritual strength to obey the Lord, but we're still responsible for our sins. This is why we need a Savior! If spiritual responsibility was based on spiritual power, then we would bear no responsibility because we have no power.
Moral responsibility is based on God's character and our basic humanity. Certain attitudes are innately right because God is that way. The human race turning sinful because of Adam didn't change God. God is still love, so love is the right way to be. God created the human race to serve Him. Our moral accountability is based on our being made in God's image.
God is self-controlled, wise, composed, and has the power to choose. God decides to whom he will show mercy, and on whom he will punish for sin. This is what God meant when He told Moses, “I will have mercy on whom I will have mercy, and I will have compassion on whom I will have compassion” (Ex. 33:19, Rom. 9:15). We can never presume on God's mercy. Sometimes God is kind (especially where there is ignorance), other times He is severe.
Predestination certainly is a hard doctrine to understand, but we should not divide over it. The Evangelical Free Church allows many different opinions about this doctrine. We should take comfort in the fact that God is in control, from beginning to end, even if we don't fully understand how. We should also be patient with one another, as we struggle to understand the more hard-to-understand teachings of God's Word.