Death before the Fall:
Simply put, the evolutionary idea of millions of years is completely opposed to the Bible's teaching about death. Evolution says that during the course of millions of years, death, bloodshed, suffering, disease, and extinction eventually led to man's existence. So when evolutionists talk about millions of years, they are not merely referring to a large number. They are imagining a long period of history in which certain events took place.
The fossils, which the evolutionists say represent millions of years of history, are a record not of life, but of death. And in many places around the world we see evidence of massive and violent carnage in fossil graveyards containing millions of former living creatures packed in high concentrations.
But the biblical teaching on death is very clear and consistent from Genesis to Revelation. There is so much I could expand on this topic, but I will sum it up (and if need be, explain it later in full detail). When Adam and Eve sinned, death and corruption entered the world. The whole earth was cursed again at Noah's Flood (Genesis 8:22). All of creation now groans in bondage to corruption, waiting for the final act in the redemption of Christians - giving them immortal resurrected bodies (Romans 8:19-25). When that redemptive event happens, we will see the restoration and redemption of all things (Acts 3:21, Col 1:20). To accept millions of years of animal death before the Creation and Fall of man contradicts and destroys not only the Bible's teaching on death but also undermines its teaching on the full redemptive work of Christ.
If God cursed the earth with thorns after Adam sinned (as Genesis 3:18 says, "both thorns and thistles is shall grow for you"), then why do we find fossil thorns in rocks that the evolutionists claim are about 350 million years old? If the millions of years are true, then God lied. If Genesis 3:18 is true, then evolution claims about millions of years are a lie. Were arthritis and cancer in the "very good" world before man sinned? If the evolutionists' dating methods are correct, the answer must be "yes." Many kinds of disease have been found in the fossil record, including arthritis and tumors in dinosaur bones dated to be 110 million years old. If the Bible is true, then those dates are false and there was no pre-Fall death and disease.
Evolutionists believe that over the course of a half billion years there were five major extinction events/periods, when 65-90% of all species living at those particular times went extinct. If this was the way the creation was for millions of years, then what impact on the creation did the Fall have? None. Contrary to what the Bible says, the Fall would have only caused spiritual death in man. We have never seen in human history the kind of mass-kill, extinction events that the evolutionary geologists say occurred before man came into existence (unless, that is, we accept the global Flood of Noah's day, but that is the very event that old-earth proponents reject). So, if the millions of years really happened, then the Fall actually improved the world from what it was in the "very good" pre-Fall creation, and would actually be a "blessing," which is absolutely absurd.
I conclude here then that if the Bible's teaching on death, the Curse and the final redemptive work of Christ is true, as it surely is, then the millions-of-years idea must be a grand myth, really a lie. Conversely, if the millions of years really happened, then the Bible's teaching on these subjects must be utterly false, which is devastating for the gospel.
The Nature of God:
Closely related to this issue of death is the incompatibility of the idea of millions of years with the character of God, as revealed in Scripture.
God spoke and things immediately came into existence, as both Genesis 1 and Psalm 33 state. It is difficult to imagine how God could say "let there be light" and then need to wait millions of years for light to appear. These facts support the conclusion that all the other divine acts in Genesis 1 were essentially instantaneous or occurred in a miraculously short period of time. Conversely, there is nothing in the text that indicates that thousands or millions of years would have been required for God to accomplish His objective in each act of creation.
If the gap theory is true, then what kind of God is it who would create the earth and all forms of life, except man, and let them live and die for millions of years and then destroy them all (in a supposed flood associated with Satan's fall) before He recreated the world with creatures very similar to the ones He had already destroyed?
If the day-age view or framework hypothesis or any other old-earth view is true, then what kind of God is it who would create the world instantly and then leave it covered with water for millions of years and then create dry land and plants and let them produce for millions of years before He made the sun? And what kind of God would make the sun, moon, and stars with the purpose of enabling man to measure the passage of time, but then wait billions of years before He made man to measure time periods? That makes God out to be quite foolish.
Or if we reject the order of events in Genesis 1 and say that the evolutionary order of appearance of the different creatures and the time-scale are correct, we have other theological problems. What kind of God would create the earth 4.5 billion years ago and let it exist for one billion years before He made the first microscopic creatures and then wait another 2.875 billion years before He made the first metazoans and then waited another 625 million years before He made Adam, who was the ultimate goal of His creation and was made to rule over all the animals, most of whom lived and died before Adam was created? This is a bizarre, wasteful God, and nothing like the wise and omnipotent Creator revealed in Scripture.
And if God really created in the order and over the long time-scales that evolutionists claim, does this not make God a deceiver and a liar or at least a very incompetent communicator when He inspired Moses to write the Genesis 1 account of the order of His creative acts, which is so contradictory to the evolutionary order of events of history? Furthermore, could the God of Scripture really describe as "very good" a fossil graveyard of thousands of feet of sedimentary rocks covering the whole earth containing billions of fossils of former living things? Could He really call cancer (as seen in dinosaurs bones) "very good?" If God called all this death "very good" and if God told Adam that thorns were a consequence of his sin when in fact they existed long before he was created, then again God lied or He is totally incompetent in His use of language. But the biblical God is the God of truth, and as the Author of all language He is fully capable of saying exactly what He means. The acceptance of millions of years is an assault on the character of Almighty God.
Only young-earth creationism gives us a view that is consistent with the glory, wisdom, power, holiness, truthfulness, and omnipotent intelligence of the God revealed through the pages of Scripture.