Hear, O Israel: The Lord our God, the Lord is one. You shall love the Lord your God with all your heart and with all your soul and with all your might. And these words that I command you today shall be on your heart. You shall teach them diligently to your children, and shall talk of them when you sit in your house, and when you walk by the way, and when you lie down, and when you rise. You shall bind them as a sign on your hand, and they shall be as frontlets between your eyes. You shall write them on the doorposts of your house and on your gates.
Being a follower of Christ is not a simple exercise in thinking the right things theologically. Rather, it demands loving Him and following Him with all of your heart, soul and mind. Or as one commentary rather wordily puts it: with perfect sincerity (heart), utmost fervor (soul) and the fullest exercise of an enlightened reason (mind).
Leave any one of those things out and you are left with distorted image of Christ, which in turn shortchanges your relationship with Him.