We are often told, based on James 2:10, that all sin is equal. Stealing a stick of gum, for example, is equal to murder. Is that really the case? I contend that the answer is no. Not only is this an unbiblical belief based on a single misquoted verse, it is actually very dangerous, and can lead to some very reckless behaviour.
As with any Bible verse, context matters. James 2:10 is neither a stand alone verse, nor has it ever been intended to be read as such. As it happens, in the very next verse, James clarifies what he means. The law itself is not important. Rather, the sin lies in disobedience to God. The same God who said "do not commit adultery" also said "do not murder". Therefore, all sin is offensive to God and worthy of punishment.
Elsewhere in the scriptures, we see clear evidence that God does not count all sin equally. We see different punishments for different crimes in the Old Testament law. We see God referring to kings doing "greater evil" than their predecessors. Jesus, when speaking to Pilate, said that because Pilate wouldn't have the power to crucify Him had it not been given by God, Judas had the greater sin. Sexual immorality is in a category of its own, as it is said to be a sin against your own flesh.
And of course, this is all common sense. If anyone has ever sinned against you, you know not all sin is equal. I wasn't as angry when my brother swore at me as I was when the criminal punched me in the head and tried to steal my camera. The two just don't compare.
Neither does sin in the heart vs. sin in the real world. For example, Jesus tells us that to look at a woman with lust is adultery. So, imagine a man lusts after a woman. Is he therefore justified in thinking "well, I've already committed this sin, so I might as well go all the way"? Obviously, the answer is no. It should stop at the lust.
And this is actually where the danger comes in. See, realistically, there are only two ways you can take it. Either "small" crimes are as bad as "big" crimes, or "big" crimes are as "good" as "small" crimes. If you take the first option and see all sin as being equal to murder, that might help you avoid sin, to an extent. But were all sinners, always (1 John 1:8), and so the only logical way to go is to effectively be able to justify anything. I remember a pastor told a story from his youth. Two of his friends had had premarital sex, and the woman confessed to him. Her justification? "Well, all sin is the same, so really what we did was no worse than stealing a pencil".
You see, then, that this mentality is not only unbiblical, but also dangerous. By putting all sin on the same level, you are capable of justifying anything. It is far better to put sin in its place. Ideally, we'll never sin at all. Don't steal, don't lust, don't fornicate, don't murder, but above all, do not risk justifying sin by making it all equal. Sin is equal because of who it is against, not because of what you did against Him.