Root and Branch
It is impossible to maintain the power of godliness where the doctrine from whence it springs is unknown, corrupted, or despised. And, on the other side, where men are weary of holiness, they will not long give entertainment to the truth; for as to their desires and affections, they will find it not only useless but troublesome."
--John Owen, Works, Volume 7, p. 188.
(There is nothing new about the gospel-centered movement. We're just recovering what the Puritans used to teach.)