From “How to become a Christian”: Chapter 6 – The bad news first – sin and its consequences.
Why should God be so concerned about our sin and why should it make such a difference? The answer is that He is perfectly holy. We will never be able to understand God, or the gospel, unless we grasp this concept of His holiness. It is largely forgotten or ignored in the modern Western church. Therefore, even within churches, holiness is either not understood at all, or it is seriously misunderstood.
It tends to bring to mind images of someone who is stuffy and pompous. Yet that has nothing to do with it. Holiness is a quality that only God has. It is His utter sinless perfection and His absolute cleanness and righteousness. It means that in every way and at all times He is perfect. There is no evil in Him or any deception or selfishness or cruelty or any other form of wickedness. He is completely good and virtuous, to a degree that we cannot imagine.
Because of God’s infinite holiness, it means that He cannot, and will not, allow any person to be in His presence unless they are equally holy. Thus, even one sin in your life will wreck the relationship between God and you. God has to be true to His nature and above all to His own holiness. He cannot compromise on that by ignoring or overlooking sin of any kind. Let’s look closer at God’s holiness and why it is so important:
“Holy, holy, holy, is the Lord God Almighty”Revelation 4:8(b) (NIV)
15But just as he who called you is holy, so be holy in all you do; 16for it is written: “Be holy, because I am holy.”1 Peter 1:15-16 (NIV)
I am the LORD who brought you up out of Egypt to be your God; therefore be holy, because I am holy.Leviticus 11:45 (NIV)
It is the LORD of hosts whom you should regard as holy. And He shall be your fear, And He shall be your dread.Isaiah 8:13 (NASB)