As mentioned earlier, we are not to fake it in church. This means first and foremost “speaking truthfully” to our fellow believers.
Yet there is an important corollary to this: “in your anger, do not sin.” If one reads this verse on its own, it might seem the point is not to express one’s anger, but actually the point is not to suppress one’s anger. This is why Paul says, “Do not let the sun go down while you are still angry.”
There are two ways one might try to avoid the sun going down on one’s anger. One is to work diligently to convince oneself, “I’m not still angry with that person.” The other, which is much more effective, is to act appropriately on the anger, which is in actual fact divine energy for change, by communicating with the person that made you angry in a constructive way. This is “speaking truthfully” (v. 25).
Suppressing anger can do great damage to yourself and to a relationship you treasure. You can tell yourself you aren’t angry, but you are, and the relationship with that person will be slowly eroded away if you continue down this path. It’s not worth it. Take a chance: go and speak the truth in love. In so doing, you may just find kindness, compassion, and forgiveness (4:32).