I don't believe that one sin is what condemns us. I don't believe it's that one time you lusted in your heart or stole that candy bar that sends us to hell.
I have a close friend that believes God condemns us for eternity for metaphorically running one stop light, he says, "God is unjust for doing that". I don't think that is the case. We are not righteous people who sin here and there or once in our life. We are sinners. The point of the Bible isn't to tell us all the things we aren't supposed to do and what we are to do. It's to tell us what we can't do, it's to show us our nature and ultimately our need.
You might think you are a good swimmer, but when some book comes along and says to be a good swimmer you have to swim 5 miles in one minute and you tried, you would realize then you aren't a good swimmer and not even close to a perfect swimmer. The Bible tells us what righteousness looks like, it says "don't look at a women lustfully" or "don't hate" try that for just a year and you'll realize you aren't that good of a person.
Jesus says "that whosoever is angry with his brother without a cause shall be in danger of the judgment" and "that whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart".
That didn't make sense to me, I thought he was trying to say "don't lust and don't hate". The problem these days is people start seeing the Bible as a list, instead of a mirror. A list tells you what you need to do and don't do, a mirror shows you your flaws and what you look like. The Bible does that to our heart, shows us that we aren't good people, but sinners.
Jesus says "unless you surpass the righteousness of the Pharisees you will not enter the kingdom of God". The Pharisees were the religious leaders in Jesus' day, think pastors, priests, Bible teachers, etc. Everyone looked up to the Pharisees to see what "righteousness looked like" because the Pharisees kept the Law, they tithed, prayed, kept everyone and themselves in check with sin, even obeying the Sabbath day. Jesus said we had to be more righteous than the pharisees.
This is the whole point of this blog and the Bible, so please get this:
Jesus wasn't saying, "the Pharisees are keeping the commands, but you need to try harder if you want to enter the Kingdom of God", Jesus was saying "you will never be able to obtain righteousness on your own, so give up, come to me, repent and I will make you righteous".
If you want joy, repent. That stuff hasn't been making you happy anyhow.