"What is the value of well-trained and well-informed Christians and spiritual leaders when their hearts remain ignorant? What is the value of great theological erudition or great pastoral adeptness or intense but fleeting mystical experience or social activism when there is not a well-formed heart to guide a well-formed life?" (Nouwen, Henri J. M.; Spiritual Formation: Following the Movements of the Spirit; K 177)
This is a rhetorical question. The correct answer is: "None." Or, perhaps: "Little."
In the Jesus-life the heart comes before the head. Apart from a heart connected to Jesus, we can do nothing.