Thou Fool

What does the Bible say about calling your brother a fool? (Matthew 5:22 KJV) “… but whosoever shall say, Thou fool, shall be in danger of hell fire.”
In professing Christendom, there is much confusion about the faith that saves. Many believe it to be their faith that saves them, and so when they stop believing they think that they have lost it. As we consider our text, we have to ask ourselves why Paul would refer to faith as a mystery, especially when Hebrews 11 records the faith of people as far back as Abel. People like Abel, Enoch, Noah, Abraham, Sarah, Isaac, Jacob, Joseph, Moses, Joshua, Rahab, Gideon, Barak, Samson, Japhthae, David, Samuel, and the prophets all exhibited faith.