For many years as a young person I always wondered why Jesus said that only God is good and nobody else should be called a good person. It was in high school when it hit me that actually Christ was right. We cannot call anybody a good person. It doesn't mean that people cannot do good things but it is only an example of goodness. You are probably wondering what I mean.
Probably all of us know at least one person that we could identify as a decent, "good" person. Mostly we use this expression when we have similar values, similar interests, or something else that makes us attracted to that person. But often if we reach out to someone that is not in our same circle, we would receive a completely different assessment of that person's "goodness." Why is it like that? Because we look at people from our own perspective, our likes and dislikes. We want to be friendly and we protect ourselves from being criticized by others. But the truth is that we have some good aspects and those come from God, and yet we do bad things and that comes from Satan.
God is the only one that can be called Good. Just imagine for a moment that you tell your friend that he or she is not good and they have to repent.
But this is an universal truth. Every single person has to repent.This is our way to get better, to come closer to being good. Don't get discouraged because you do not have all the virtues on earth and because you commit a sin. If we were to be perfect, Jesus Christ would never show how much He loves us. People are people and in this simplicity God offered us the biggest gift, His son. So do everything to be better and grasp the grace that comes to you from God.