One of the most serious errors we can make about heaven is to believe we can get there by our own good works. We imagine that God puts our good deeds and our bad deeds in a balance, and whichever side weighs more will determine our salvation.
But it isn't true–and the reason is because God is perfect, and even one sin is enough to keep us out of His holy presence. The Bible says, "For whoever keeps the whole law (of God) and yet stumbles at just one point is guilty of breaking all of it" (James 2:10).
Have you ever seen a program on the way computer chips or antibiotics are made? Manufacturers go out of their way to make them in a totally clean laboratory–because even one particle of dust could contaminate them and make them useless. In a far greater way, even one sin will contaminate us and keep us from God's presence.
But this is why Christ came! We are sinners–but He was sinless, and when He died on the cross all our sins were transferred to Him. He took the judgment and hell we deserve, and when we trust Him as our Lord and Savior, His righteousness is transferred to us. Don't trust in your own goodness for your salvation. Instead, trust Christ and by faith ask Him to come into your heart today. He alone can save you–and He will.