If you know these things, happy are you if you do them.
All Commentaries on John 13:17 Go To John 13
Cyril of Alexandria
AD 444
If therefore ye understand these things, He saith----that is, "if ye can clearly perceive the meaning of what I am saying,"----blessed are ye if ye do them. For it is not the knowledge of virtue, but rather the practice of it, that may well be pronounced worthy of both love and zeal. And I think that perchance it may be even better never at all to have learned, than after so learning to hamper one's mind with the bonds of indolence, and refuse to carry out in action what one knows to be the best and right course; according to the saying of the Saviour: He that knew not his lord's will, and did it not, shall be beaten with few stripes; but he that knew it, and did it not, shall be beaten with many stripes. For in the case of a man who has sinned in total ignorance, it would not be at all unseemly for him, if perchance he were being visited with correction for his carelessness, to ask for a partial forgiveness: but in the case of one who knew what he was doing, that knowledge would become grievously weighty towards his condemnation. For though nothing was wanting to enable him, yet he disdained to do what was right and seemly. Knowledge therefore must lead to action: for then, clothed with perfect confidence in our citizenship in Christ, we shall receive in due season our most plenteous reward. As an instance of this, the Saviour said that whosoever did and taught [His commandments] should be called great in the kingdom of heaven: and that very justly, for what is wanting to such a man to make his goodness perfect? And whensoever a man can show that he can take to himself full credit for good deeds, then surely he will be able to glory in receiving most perfect gifts from God. And so whenever actions go hand in hand with knowledge, then assuredly there is no trifling gain; but when either is lacking, the other will be very much crippled: and it is written: Even faith apart from works is dead. Although the knowledge of God Who is One even in nature, and the confession of Him in guilelessness and truth is all included in faith, yet even this is dead, if it is not accompanied by the bright light which proceeds from works. Surely therefore it is utterly profitless merely to know what is good and yet to be undesirous to practise it at once. For this reason then He says that His own disciples, and so also all that believe on Him, will be blessed, if they have not only grasped the knowledge of the words spoken by Him, but are also fulfilling those words by their deeds
