I came across this practical application while studying 2 Peter 1:1-4.
"In our day we are rightly warned about the danger of a sterile faith, of a 'head' knowledge that never touches the heart. But we need equally to be careful of a 'heart' knowledge that never touches the head! Too many Christians know too little about their faith, we are therefore often unprepared to explain how our 'God' differs from the 'God' of Mormonism or of the Jehovah's Witnesses. Again and again the New Testament makes plain that our very salvation can depend on confessing truth about God and his revelation in his Son. The biblical writers demand a 'knowledge of God' that unites head and heart. We must be careful not to sacrifice the head in favor of the heart."
Douglas J. Moo, 2 Peter, Jude, Grand RapidsL Zondervan, 1996, 39.