Let's say you invite your best friend to your home for brunch. Your specialty is scrambled eggs. While the two of you chat you prepare the meal. Your famous recipe calls for five eggs but when you open the egg carton there are only four eggs in it.
Well, you decide to make do with what you have so you crack open each egg and drop it in the bowl. But as you are mixing the eggs you just know it's not going to turn out right without the fifth egg. So you search through the refigerator and there clear in the back is an old egg carton with one egg in it! Cool! So you crack open that egg and drop it into the bowl. EEWWWW! What's that smell? You look down and realize that that egg was rotten!
Now here's the big question.....would you go ahead and mix the rotten egg in with the rest, cook them up and serve them to your friend? Of course not! Even though there were four good eggs in the bowl that ONE rotten egg spoiled the whole bunch. That is the way it is with sin. No matter how many good things we do it only takes ONE SIN to keep us from being perfect. God's standard is perfection and if we are going to get to Heaven on our own merit we will have to be perfect.
But the good news of the gospel is that Jesus lived the perfect life for us and then took the punishment we deserve on the cross. He paid the debt for our sins. But we must turn to Him, ask forgiveness and follow Him.