A tree is identified by its fruit. Figs never grow on thornbushes, nor grapes on bramble bushes. 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. What you say flows from what is in your heart. — Luke 6:44-45
The British Museum in London received an ancient artifact, a painted rock, in 2005. Titled "Early man venturing towards the out-of-town hunting grounds," it featured animals, a man, and a curious tool. After being on display for three days, the museum removed the artifact from its exhibit. It turned out that the "curious tool" painted on the rock was a shopping cart! A notorious hoax artist was responsible for getting it into the museum, where it remained until experts realized the piece was a fake.
People have the ability to show a certain personality on the outside while being something different internally. And just like the museum's "artifact," one's outward personality can be seen as legitimate if concealed well enough. However, there will come a time when something--a phone call, a speeding driver, a crisis--will expose the person's true identity. The hoax-life will be revealed. Unless our outward appearance matches our inward appearance, we will be exposed for who we are inwardly.
Jesus said, "A good tree can't produce bad fruit, and a bad tree can't produce good fruit" (Luke 6:43).
Likewise, a person claiming to know Jesus as Forgiver and Leader should not go around berating or threatening his or her coworkers. These attitudes diminish one's potential witness for the Lord, giving those who don't know Jesus "valid" reasons not to believe him. Sooner or later our outward appearances will drown out our inward claims. We should be doing our best to exhibit Christ in the most positive light we can. Otherwise, our words and actions will be revealed as hypocritical.
Let's be real--to ourselves, to others, and to God--and help others to be the same. That way, the only inward thing that will be exposed is the Lord we love and follow.