He, therefore, who liveth in these Christians hath ‘purified their hearts by faith;’ insomuch that every one that has Christ in him, ‘the hope of glory, purifieth himself even as he is pure.’ He is purified from pride; for Christ was lowly in heart: He is pure from desire and self-will; for Christ desired only to do the will of his Father: And he is pure from anger, in the common sense of the word; for Christ was meek and gentle. I say, in the common sense of the word; for he is angry at sin, while he is grieved for the sinner. He feels a displacency at every offence against God, but only tender compassion to the offender.
Thus doth Jesus save his people from their sins, not only from outward sins, but from the sins of their hearts. ‘True,’ say some, ‘but not till death, not in this world.’ Nay, St. John says, ‘Herein is our love made perfect, that we may have boldness in the day of judgment; because, as he is, so are we in this world.’ The Apostle here, beyond all contradiction, speaks of himself and other living Christians, of whom he flatly affirms, that, not only at or after death, but ‘in this world,’ they are ‘as their Master.’
[Excerpted from A Plain Account of Christian Perfection]