There are Christians who like to quote scripture to point out peoples sin. Of course scripture is correct in that act, whatever the act scripture is against, is a sin. The problem is the heart of the person, who is quoting it as a weapon. The purpose of the Old Testament is to prove beyond any doubt that there has never been, and never will be, a human being who can live up to God's standard. Jesus joked about this while calling these types of Christians hypocrites. "'Let me take the speck out of your eye,' when all the time there is a plank in your own eye"?
So if you claim to be a Christian then you are recognizing that we're all sinful, flawed creatures, in need of God's grace and a savior. Why then would you quote scripture to people who don't claim to be Christians? The Bible says "we are all born slaves to sin free from the obligation to do right". They need your prayers not your instruction or even worse criticism. You should be begging God to awaken them. As Jesus prayed for those crucifying Him "forgive them Father for they do not know what they do"! Jesus wasn't yelling "turn or burn you heathens".
But what about those who do claim to be Christians and yet they are living in ways that don't line up with the Bible? The first sin that seems to be the most offensive to certain Christians is homosexuality. Perhaps premarital sex is 2nd but it's usually a distant 2nd. And yes these are sins! But yelling it at the people involved doesn't turn their hearts towards God. Which is what a brother or sister in Christ's goal should be. To return the gaze of the sinner from their sin back towards their creator and savior. The goal isn't to prove that you know more scripture than someone else.
The most religious people of Jesus's time were the Pharisees. The name Pharisees means "set apart". They constantly studied the Jewish law, knew it better than anyone else and believed it. They also followed it as best they could. Yet these are the people Jesus had the biggest problem with. Why? In Matthew 23 Jesus explains that the Pharisees are experts in the law so obey what they teach you but do not do as they do. Well what did they do? They made it hard to love God. Following Jesus is easy compared to what some people want to make it seem. Jesus says "my yoke is easy and my burden light". Obviously this means that the yoke of others is hard and the burden heavy. Jesus went on to call the Pharisees "show offs". But these are the people who know the law better than anyone, and are simply telling others about it. Not according to Jesus. By using scripture as a weapon to hurt people He said "you are locking people out of heaven. You will not get in yourselves and are keeping others from going as well"!
All sins come from the heart. The sinful act is like taking your temperature and seeing you have a fever. Getting the temperature right isn't the goal. Fixing the condition that gave you the temperature is the goal. Then the temperature will correct itself. You don't stop lust by resisting sex. You stop lust when your Father replaces it. That's true of all sins, which God points out are all offensive. They are not all equal, but God can no more be in contact with someone who is really proud than He can a murderer. And yet the murderer and the proud can both be forgiven because Jesus accepted their punishment. Once you grasp what Jesus did for you...had to do for you, because you are a sinner, all pride should be wiped out.
So if you want to quote the Bible that's awesome! But first make sure you have read it cover to cover. Then you can quote it in context. If you only read a couple of books in the Bible like say Leviticus and Revelation you would be clueless. Even worse is just reading some of the stories. Hosea is ordered to marry a prostitute. Really? Abraham is ordered to sacrifice his son. What?!? God comanded the Jews to not mix linen with wool clothing. Huh? On a more severe note God also ordered the Jews to destroy the Amalekite people... women, children, and pets.
If you only read this, or quote from this part of the Bible, you don't put these things in their proper context and you end up with a very flawed image of God and the purpose of the Bible. More importantly rather than separating yourself from sin and pointing out everyone else's sin like a Pharisee, try following Jesus's example of getting into the muck of life and help guide people to the Father. Remember Jesus is our connection to the source of life. He says "I'm the vine and you are the branch. If you are with me you will produce much fruit. Apart from me you can do nothing".