Irenaeus from “On the Apostolic Preaching”
For the way of all those who see is single and upward, illumined by the heavenly light, but the ways of those who do not see are many, dark and divergent; the one leads to the kingdom of heaven, uniting man to God, while the others lead down to death, separating man from God. Thus it is necessary for you and for all who are concerned about their salvation to make [your] way by faith, without deviation, surely and resolutely, lest, in slacking, you remain in gross desires, or, erring, wander from the right.
That last sentence is a prelude to a more extended discussion by Irenaeus about the importance of keeping holiness of body and of soul. Holiness of the body, he writes, is abstaining from all “shameful and lawless deeds.” Holiness of the soul is to know and keep the whole truth of the faith without adding to it or subtracting from it.
He asks, “For what use is it to know the truth in words, only to defile the body and perform evil deeds? Or what profit indeed can come from holiness of body, if truth is not in the soul? For these rejoice together and join forces to lead man to the presence of God.”
For Irenaeus, at least, orthodoxy without bodily holiness is useless. Bodily holiness without orthodoxy profits us nothing.
Irenaeus, of course, was just man. His teaching could be false. Many Protestants, for instance, might resist what appears to be a form of works righteousness not just here but in the rest of his writings.
But I find his linking of holiness of body and holiness of soul a good reminder that we should not place too much emphasis on one to the neglect of the other.