" You can learn from anybody if you just know the right questions. The Bible says, “Counsel in the heart of man is like deep water; but a man of understanding will draw it out” (Prov. 20:5 KJV). In other words, you can learn from anybody if you just learn to draw out his or her knowledge. And how do you do it? You draw it out by asking questions. We all know things that others don’t, and others know things of which we are ignorant. That’s why the Bible says, “Iron sharpens iron” (Prov. 27:17). "

― John Piper , Thinking. Loving. Doing.: A Call to Glorify God with Heart and Mind