About 3 minutes to read
I can be good without God
In one sense you can, and Christians have never denied it. God’s law is written on every heart, so men who never read a Bible know a great deal about right and wrong (Romans 2:14-15). But good by whose measure? Jesus said the first and great commandment is to love God himself with everything you are (Matthew 22:37-38). A man can be kind to his neighbor and break that commandment every day he lives. Even his good works, the Confession says, are sinful and cannot please God, because they do not come from a heart purified by faith or aim at the glory of God, though leaving them undone would be more sinful still (WCF 16.7, Hebrews 11:6).
Morality is only evolution or culture
If morality comes only from evolution, it tells you what kept your ancestors alive and nothing about what you ought to do. Nature has produced cruelty as surely as kindness, and it cannot tell you which is right. If it is only culture, then no culture can ever be wrong, and the men who ended the slave trade were not right, only different. No one lives that way.
You say torturing a child for fun is wrong everywhere and always, and you are right. That is a law above every culture. You might call it simply a fact, like two and two making four. But a sum does not accuse you, and you wrong no one when you add it up badly. A law that binds every man and accuses him when he breaks it needs a Lawgiver with the right to bind him. His law is no whim, as if he could have made cruelty good. He commands what agrees with his own nature, and he cannot deny himself (2 Timothy 2:13). And you do not only know that law. You hold other people to it every time they break their word to you or run you down behind your back, and you have done both.
Therefore thou art inexcusable, O man, whosoever thou art that judgest: for wherein thou judgest another, thou condemnest thyself; for thou that judgest doest the same things.
Romans 2:1 (KJV)
Under every objection
What God Calls You To Do
An objection can be answered and a man still stay away. Jesus said that men loved darkness rather than light, because their deeds were evil (John 3:19). The trouble between you and God is not finally an argument. You have sinned against him, and you know it.
Christ came for sinners exactly like you. He kept the law you have broken, and on the cross he bore its curse for everyone who trusts him, and God raised him from the dead. So the call is the one Jesus preached. Repent, and believe the gospel (Mark 1:15). You do not have to settle every question first.