To make us meet to be blissful partakers of such heavenly company, this ‘marred clay’, I mean, these depraved natures of ours, must necessarily undergo an universal moral change. Our understandings must be enlightened; our wills, reason and consciences, must be renewed; our affections must be drawn toward and fixed upon things above. And because flesh and blood cannot inherit the kingdom of heaven, this corruptible must put on incorruption, this mortal must put on immortality. And thus old things must literally pass away and behold all things, even the body as well as the faculties of the soul, must become new.
This moral change is what some call, repentance, some, conversion, some, regeneration. Choose what name you please, I only pray God, that we all may have the thing. The scriptures call it holiness, sanctification, the new creature and our Lord calls it a ‘New birth, or being born again, or born from above.’ These are not barely figurative expressions, or the flights of eastern language, nor do they barely denote a relative change of state conferred on all those who are admitted into Christ’s church by baptism. But they denote a real, moral change of heart and life, a real participation of the divine life in the soul of man. Some indeed content themselves with a figurative interpretation but unless they are made to experience the power and efficacy thereof, by a solid living experience in their own souls, all their learning, all their laboured criticism, will not exempt them from a real damnation. Christ hath said it and Christ will stand, ‘Unless a man,’ learned or unlearned, high or low, though he be a master of Israel as Nicodemus was, unless he ‘be born again, he cannot see, he cannot enter into the kingdom of God.’
The Sermons of George Whitefield edited by Lee Gatiss (Wheaton, IL; Crossway Books; 2012) Sermon 13: The Potter and the Clay