Of the Little Children on Whom He Laid His Hands; Of the Rich Man to Whom He Said, Sell All that You Have; Of the Vineyard in Which the Labourers Were Hired at Different Hours; And of the Question as to the Absence of Any Discrepancy Between Matthew and the Other Two Evangelists on These Subjects
123 Matthew proceeds thus: “Then were there brought unto Him little children, that He should put His hands on them, and pray; and the disciples rebuked them;” and so on, down to where we read, “For many are called, but few are chosen.” Mark has followed the same order here as Matthew. But Matthew is the only one who introduces the section relating to the labourers who were hired for the vineyard. Luke, on the other hand, first mentions what He said to those who were asking each other who should be the greatest, and next subjoins at once the passage concerning the man whom they had seen casting out devils, although he did not follow Him; then he parts company with the other two at the point where he tells us how He steadfastly set His face to go to Jerusalem; and after the interposition of a number of subjects, he joins them again in giving the story of the rich man, to whom the word is addressed, “Sell all that you have,” which individual's case is related here by the other two evangelists, but still in the succession which is followed by all the narratives alike.
For in the passage referred to in Luke, that writer does not fail to bring in the story of the little children, just as the other two do immediately before the mention of the rich man. With regard, then, to the accounts which are given us of this rich person, who asks what good thing he should do in order to obtain eternal life, there may appear to be some discrepancy between them, because the words were, according to Matthew, “Why do you ask me about the good?” while according to the others they were, “Why do you call me good?”
The sentence, “Why do you ask me about the good?” may then be referred more particularly to what was expressed by the man when he put the question, “What good thing shall I do?” For there we have both the name “good” applied to Christ, and the question put. But the address “Good Master” does not of itself convey the question. Accordingly, the best method of disposing of it is to understand both these sentences to have been uttered, “Why do you call me good?” and, “Why do you ask me about the good?”
Source: The Harmony of the Gospels (New Advent)