And Jesus said unto him
The same as in Mt. 19:17, (See Gill on Matthew 19:17).
Why callest thou me good?
This is said, not as denying that he was good, or as being angry with him for calling him so, but in order to lead this young man to a true knowledge of him, and his goodness, and even of his proper deity:
there is none good, but one, [that is], God;
some render it, "but one God", as the Vulgate Latin, Syriac, and Arabic versions; and so the words are a proof of the unity of the divine being, and agree with ( Deuteronomy 6:4 ) , but are not to be understood to the exclusion of the Son and Spirit, who, with the Father, are the one God: nor do these words at all militate against the deity of Christ, or prove that he is not God, as the Jew objects F1; seeing this is not to be understood of the person of the Father, in opposition to the Son and Spirit, who are equally good: nor does Christ, in these words, deny himself to be God, but rather tacitly suggests it; since he is good in the same sense in which God is good: in Matthew it is added, "but if thou wilt enter into life, keep the commandments", ( Matthew 19:17 ) : this Christ said not as his sense, that the way to eternal life lies in keeping the commandments of the law; but he speaks in the language of the Pharisees, and of this man; and his view is, to bring him to a sense of the impossibility of obtaining eternal life by these things, as the sequel shows: wherefore the above Jew F2 has no reason to confront the followers of Jesus with this passage, as if it was a concession of his, that it is impossible any should be saved without keeping the commands of the law of Moses.
F1 R. Isaac Chizzuk Emuna, par. 2. c. 19. p. 408.