In the Bible, Jesus warns about false prophets who look like good guys but really are bad news (Matthew 7:15). He uses the illustration of a tree to point out how we will know the good from the bad. A good tree bears good fruit, but a bad tree bears bad fruit (Matthew 7:15–20).
Imagine having two apple trees in your yard. As spring comes, beautiful, sweet-smelling blossoms bloom on both. When you pick the apples, however, one tree bears sweet, juicy McIntosh apples. They get made into delicious pies, crisps, and applesauce. The other tree produces apples that look just as good, but when you sink your teeth into one, it is sour and bitter. It’s a crab apple tree: worthless except for feeding the birds.