Even though we are Christians, a forgiven people, we still struggle with remaining sin. God in His ultimate wisdom did not choose to translate us immediately to heaven the moment we were converted. His desire is for us to learn how to love Him, over the course of our lives, when there is an adversary close to the breast.
We are not to become so aware of this enemy within that we cease fighting the enemy without. Far from being an example of pious warfare, this is nothing but abdication and surrender. At the same time, we must be aware of our own infirmities to the extent that they interfere with what God has commanded us to do.
Because we are Christians, we have standards for human behavior that we find in the Bible. Because we are Christians who struggle with remaining sin, we consistently apply those standards to everyone else. So rather than being characterized by forgiveness, tender mercies, relief, joy, and overflowing kindness to everyone else, we scrunch our faces into a censorious shape, purse our lips, and walk about thou-shalt-notting. We find, and immediately join, the fellowship of the grievance. We band together with the company of the peeved. It does not matter what the complaint is—this deep fellowship requires only that you have one. Your grievances vary; all that matters is that your expression be a sour one.
Brothers and sisters in the Lord Jesus—this is not right. Has God been kind to you? Then spread it around. Be kind to one another, tender-hearted, forgiving one another—just as God in Christ forgave you. This is basic. If any one human being starting extending to others just a tiny fraction of the kindness God has shown to us, his face would be on the cover of Newsweek next week. And he would probably be executed the week after. Such a person would be a real nuisance; he would not leave our grievances alone.