When the head spring of a river is polluted it does little good to effect a cleanup operation downstream. It is the source that must be purified. The head spring of each individual is their heart, and the head spring of the human race is Adam. In both instance, according to our Lord, the source is polluted with wickedness. That is why the Christian Faith is not a matter of one following his own heart! Instead it is receiving by faith the new and clean heart our Lord promises us. This gift is made possible by Jesus' death and resurrection. Our Lord Jesus becomes the head spring of a new and redeemed humanity.