15 We have now expounded the Dispensation of the Mysteries, through which the heretics deceive certain of the unlearned into ascribing to infirmity in the divinity, what Christ said and did through His assumed human nature, and attributing to the form of God what is appropriate only to the form of the servant. Let us pass on, then, to answer their statements in detail. We can always safely distinguish the two kinds of utterances, since the only true faith lies in the confession of Jesus Christ as Word and flesh, that is, God and Man.
The heretics consider it necessary to deny that our Lord Jesus Christ by virtue of His nature was divine, because He said, Why do you call Me good? None is good save one, God. Now a satisfactory answer must stand in direct relation to the matter of enquiry, for only in that case will it furnish a reply to the question put. At the outset, then, I would ask these misinterpreters, “Do you think that the Lord resented being called good?” Would He rather have been called bad, as seems to be signified by the words, Why do you call Me good? I do not think any one is so unreasonable as to ascribe to Him a confession of wickedness, when it was He Who said, Come unto Me, all you that labour, and are heavy laden, and I will refresh you.
Take My yoke upon you, and learn of Me: for I am meek and lowly of heart, and you shall find rest unto your souls. For My yoke is easy and My burden is light</em>. He says He is meek and lowly: can we believe that He was angry because He was called good? The two propositions are inconsistent. He Who witnesses to His own goodness would not repudiate the name of Good. Plainly, then, He was not angry because He was called good: and if we cannot believe that He resented being called good, we must ask what was said of Him which He did resent.
Source: On the Trinity (New Advent)