John Lightfoot on Luke 18:19

[Why callest thou me good?] I. For the better understanding our Saviour's sense and meaning in these and the following words, I would affirm, (and who can argue it to the contrary?) that this man acknowledged Jesus for the true Messiah.

1. This several others did also, who, as yet, were not his disciples; so those blind men, when they call him 'the Son of David,' Matthew 20:30: not to mention others. And what reason can there be for the negative upon this man? Especially when he appears to be a person of more than ordinary parts and accomplishments, not only from what he tells us of himself, but from that kind and affectionate reception he met with from Christ.

2. This was no vulgar or ordinary question he put here, "What shall I do, that I may inherit eternal life?" For it seems plain that he was not satisfied in the doctrine of their schools, about the merit of good works, and justification by the law: but he thinks there is something more requisite towards the obtaining salvation, because, after he had (as he tells us) performed this law from his youth up, he yet inquireth further, "What shall I do," &c.; in which that he was in earnest, our Saviour's behaviour towards him sufficiently testified; as also that he came to Jesus, as to no ordinary teacher, to be instructed in this affair.

3. It was very unusual to salute the Rabbins of that nation with this title. For however they were wont to adorn (not to say load) either the dead or absent with very splendid epithets, yet if they spoke to them while present, they gave them no other title than either Rabbi, or Mar, or Mari. If you turn over both the Talmuds, I am deceived if you once find either Good Rabbi, or Good Mar.

II. So far, therefore, is our Lord in these words from denying his Godhead, that he rather doth, as it were, draw this person in to own and acknowledge it: "Thou seemest in thy very address to me, and the compellation thou gavest me, to own me for the Messias: and dost thou take me for God too as well as man, when thou callest me good, seeing there is none good but God only?" Certainly he saw something that was not ordinary in this man, when it is said of him that he loved him, Mark 10:21: i.e. he spoke kindly to him, and exhorted him, &c. See 2 Chronicles 18:2; Psalm 78:36: they flattered him with their mouth. Nor is it an ordinary affection this young man seemed to have for the blessed Jesus, in that he departs sorrowful from the counsel that had been given him; and that he had the person that had counselled him in very high esteem, appears in that he could not without infinite grief reject the counsel he gave him.