This passage is still a stumbling block for me, not because I don't want to love people, but because some people make it so hard to love them through their deceitfulness, lying, betrayal, selfishness, anger, bitterness, and resentment. Our brothers and sisters are those who have accepted Christ, since we are all children of God. It's God's will that not even one shall perish therefore, we must look at every person as a potential brother or sister in Christ--even if they are not yet so. God doesn't think in reality the way we do. He sees the spiritual--the future. He knows which individuals will eventually become His even if we do not. This is why, we must treat them with the same courtesy and forgiveness as He would. As this passage says, it isn't enough to say we love them, we must show it in action and deed.