"Put on the whole armor of God, that you may be able to stand against the schemes of the devil. For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places." (Ephesians 6:11-12) Do we as human beings really understand these verses? We rely on our senses to interact with the world around us; what is unseen is hard for us to quantify. I work in a manufacturing environment. Schedules are tight and when things go wrong, pressure mounts and patience wears thin. It's easy in that situation to see another person as the problem. "He needs to work harder." "Why does she keep making the same mistake?" "Why is he so obnoxious?" We see the other person as the source of our frustrations, but it's really the situation that causes frustration for everyone involved. Working together is the solution; arguing and assigning blame accomplishes nothing.
Satan uses situations like the one I just described to divide and conquer. Church, work, school, or any other situation where people interact - if Satan can manipulate that situation to his advantage, he will. He uses our human weaknesses and limitations to put us at odds with each other, thereby concealing himself as the real enemy. He wins if he can get us to see flesh and blood as the enemy rather than his unseen "spiritual forces of evil". Jesus said, "If a kingdom is divided against itself, that kingdom cannot stand. And if a house is divided against itself, that house will not be able to stand." (Mark 3:24-25) That's true for any group or organization of human beings, especially the church. If members of a congregation focus on each other's failings, then that congregation will fail. Yes, we are all sinners, but more importantly, God loves each and every one of us and is deeply concerned about our salvation. Shouldn't we have the same attitude toward each other? "The Lord is not slow to fulfill his promise as some count slowness, but is patient toward you, not wishing that any should perish, but that all should reach repentance." (2 Peter 3:9)