Matthew 12:35 A good person produces good things from the treasury of a good heart, and an evil person produces evil things from the treasury of an evil heart.
When we find ourselves doing something bad, we like to think I have a good heart...and we think that having a good heart overrides what we have just done wrong. It doesn't. That was some of the evil that is in our heart escaping out. We need to be aware that the devil tries to hide evil in our hearts and we need to guard against that evil. The devil plants thoughts in our head to do bad things... but once we have done that bad think it came from our heart. We need to be careful and think twice before acting upon a bad thought. We need to learn to ask our-self "Do I want my heart to be seen in this light?" and if the answer is now then we need to rethink how we want to react in a situation... or how we want to act in a situation. I heard this question once "I know you act like a Christian, but do you re-act like a Christian?" ... lots of times the evil hiding in our hearts comes out in our reactions... we guard our actions so well... but then when we have to re-act quickly to an unpleasant situation we don't act in a "good" way. I want my heart to produce good things.... I want to know what is in my heart is good... I want people to see me as good... more importantly I want God to see me as good...to see my heart as good. To have God and people see us as having a good heart we must produce good things. We never need to lie to ourselves by telling ourselves we are good if we we "produce evil things"... Can we do both?... so many times we do do both...but the Bible tells us in Matthew 6:24" No man can serve two masters"... God is the master of all that is good, satin is the master of all that is evil. So when we find ourselves re-acting bad, acting bad... but we love God... we need to show God that we love him by changing our actions and our reactions, after all "good things come from the treasury of a good heart." The Bible tells us so.