Recently it was put to me in a rather heated conversation that "all sin is equal". And I disagreed.
The standard argument for the "equality of sin" is that God treats all sins the same. "For all have sinned and fallen short of the glory of God" doesn't have a list of sins that does not disqualify one from "falling short". Like, "if you only tell white lies you still have the glory of God".
This is a fairly convincing argument. And completely wrong. We know it intuitively too. Punishments for sin vary widely. Typically premeditated murder is treated with more severe punishment than murder as a crime of passion (it is in the Old Testament, too). But if all sins are equal - why should there be a difference for those two types of murder - or even for the little white lies we tell.
The reason Christians think all sins are equal is because all sins lead to death. But there is no variation in death. Someone isn't more dead than someone else. So the punishment for all sins looks the same - and the Bible seems to say that all sins are judged the same.
However. This is not the case. As sins are accumulative.
For instance, someone who commits premeditated murder usually has built up a collection of sins (such as hatred, jealousy, spitefulness etc...) before getting to the murder stage. Murder isn't a "1st level sin". Maybe it starts with jealousy and works up to envy then goes on to hatred and on and on till a murder is actually committed.
This is why murder is not the same as a white lie. There are no other sins required to step up to a white lie, it is what it is - but left uncontrolled and unrepentant - it may work it's way to something worse (or may not).
And this has Biblical precedent - Romans says that God will give people over to their depraved minds at some stage if they continue in a certain lifestyle.
This is helpful in knowing which sins to be more lenient with and which sins to deal with more harshly.