But all these things will they do unto you for my name's sake, because they know not him that sent me.
All Commentaries on John 15:21 Go To John 15
Cyril of Alexandria
AD 444
He declares that those who choose to act impiously against His holy disciples will do it on no other plea than "My Name" only. For this is a reproach against those who honour God, and an excuse for setting themselves against them on the part of those who do not know Him. But since it is clear to all that no one would suffer anything for the sake of God without reward, for a glorious crown will await them, He incites them again to courage, and makes their spirit steadfast, thrusting aside the misery of that which they expect by the hope of the return. He points out then that the very perils they endure are gain and an object of prayer, and rids of all its terrors that, the very prospect of the occurrence of which might stupefy some, and exhorts His disciples to welcome it with the greatest eagerness. And indeed when they were once summoned before the impious Council of the Jews, and had been severely buffeted with stripes for the sake of Christ, they went forth from the presence of the council, rejoicing, according to the Scripture, that they were counted worthy to suffer dishonour for the Name of the Lord. And of a truth they earnestly exhort us to endure suffering in this cause, and in no way to be dismayed by it, even if we have to encounter any pain for Christ's sake. For let none of you suffer as a murderer, or a thief, or an evil-doer: but if a man suffer as a Christian let him not be ashamed; but let him glorify God in this Name. Most pleasant then is suffering for Christ's sake, and sweet is peril when its presence is occasioned by love towards God.
But consider how here again, showing Himself as One with His Father, He says that neither the Jews nor those who were about to persecute the preachers of the Name of Christ, knew either the Father or the Son. For he who deems it his duty to dishonour the Son is avowedly a hater of the Father; not indeed as transgressing against another nature, but as insulting the true dignity of His natural Divinity. For none could be convicted of insolence against the Son, if he respected the nature of the Father. And if he were at all acquainted with the actual nature of the Father, how came he to be ignorant that He was begotten by Him? And will not he who spoils the fruit produced from it injure the parent tree? Sin against the Son therefore is a convincing proof of ignorance of God the Father.
But whereas He did not say, Because they know not My Father, but Him that sent Me, I think He wished to hint at something of this kind. His aim, as it seems, was to show that those who practised persecution against His devoted servants, plainly tied their heads as it were in a noose of a double transgression. For not merely, He says, will they be convicted of ignorance of My origin, or be justly condemned on he charge of atheism, but will actually be found rebuking the true wisdom of God the Father. For if He sent His own Son to raise that which had fallen away, to renew that which was worn out, to set forth life to all in the world, while those in the world set themselves against and impiously oppose such as choose to preach Him the Saviour of the world, they will be very clearly convicted of ignorance and of fighting against Him that sent Me. For by the expression "being sent," He introduces a clear proof of His Incarnation. But he that is ignorant of Him that sent Me, shows by this very fact his ignorance of God, and dishonours the mystery of My mission.