8 “The Son can do nothing of Himself, but what He sees the Father do.” Here rises up an error of the Arians; but it rises up that it may fall; because it is not humbled, that it may rise. What is it which has set you off? You would say that the Son is less than the Father. For you have heard, “The Son can do nothing of Himself, but what He sees the Father do.” From this you would have the Son called less; it is this I know, I know it is this has set you off; believe that He is not less, you can not as yet see it, believe, this is what I was saying a little while ago.
“But how,” you will say, “am I to believe against His own words”? He says Himself, “The Son can do nothing of Himself, but what He sees the Father do.” Attend too to that which follows; “For what things soever the Father does, the same also does the Son likewise;” He did not say, “such things,” Beloved, consider a while, that you cause not confusion to yourselves. There is need of a tranquil heart, a godly and devout faith, a religious earnest attention; attend, not to me the poor vessel, but to Him who puts the bread in the vessel.
Attend then a while. For in all that I have said above in exhorting you to faith, that the mind imbued with faith may be capable of understanding, all that has been said has had a pleasing, glad, and easy sound, has cheered your minds, you have followed it, you have understood what I said. But what I am now about to say I hope there are some who will understand; yet I fear that all will not understand. And seeing that God has by the lesson of the Gospel proposed to us a subject to speak upon, and we cannot avoid that which the Master has proposed; I fear lest haply they who will not understand, who perhaps will be the greater number, should think that I have spoken to them in vain; but yet because of those who will understand, I do not speak in vain.
Let him who understands rejoice, let him who does not understand bear it patiently; what he does not understand, let him bear, and that he may understand, let him bear delay.
Source: Sermons on Selected Lessons of the New Testament (New Advent)