Don’t lie to each other, for you have stripped off your old sinful nature and all its wicked deeds.
Lying is wrong. For some reason, it seems to be a sin that we're willing to let slide. It's like we consider it a minor sin. Yet, God doesn't. All sin is a problem.
I'd say lying is almost like a gateway. I mean, if a person will willingly lie, that's not good. I'm not talking about a lie that someone didn't realize they told. I'm talking about those lies when a person looks you right in your eyes and chooses to not tell the truth.
Like all sin, it comes down to the heart of the matter. What is in your heart that makes lying OK? In Colossians, the point of this verse is to say that sin and wickedness shouldn't be a part of you any longer.
Whether or not you think it's a big or small lie doesn't change the fact that it is a lie. And if you're a believer, lying shouldn't be a part of your character. Period.