Just imagine how many people were involved in this evil act. The sin was not David sin alone. Surely the entire palace staff was fully aware of what had happened, if they chose not to say anything. David was certainly not able to write and so a scribe came in and wrote that note for him, that horrible note, but did not say anything. Joab receive the notes, and obeyed David. And not Joab alone, but all the fellow soldiers who participated in the retreat knew what was going on. So many people were involved in the evil, but no one said anything.
Why? Was it simply fear? So many people were afraid of losing their position, or even their life, but I think there is more going on here that. There is also the mentality of being part of a group. “No one is saying anything, why should I?” We humans take our cues from the actions of those around us. If we are alone, we have to think for ourselves, and surely not all of those who participated in the murder of Uriah the Hittite were actually cowards. Probably many of them simply considered it someone else's responsibility.
We need this group mentality to get through everyday life. Life would be so much more stressful if we could not follow the lead of those around us. Nevertheless, this does not excuse committing a sin. Each of those people ought to have stopped and thought about what they were doing. What they needed, was more reflection, more conscious thought about what they were doing. Probably some of them would still have been cowards, but not all of them.
This same group mentality is at work in how we engage our culture. So many things that we do, without question, are simply what everyone else is doing. We need to become a witness to those around us. Without a doubt, this is not easy. We will be, at least at first, like the tiny mustard seed. The group will turn on us and try to crush us, because they do not understand why anyone would want to be different. But the kingdom of God will grow. It appears here, and it appears there, always seeming small and weak, but it is a force growing in our world. Someday we will find that we are part of something greater, greater than ourselves, greater than we could possibly have imagined.