Consider this story as giving us a lesson concerning the connection between the hope of eternal life, or everlasting happiness, and the performance of good works.
I. I suppose that the young man in the story thoroughly believed that the eternal life of which he spoke was the greatest blessing which he could obtain. Moreover, he did not think eternal life an easy thing to be obtained; he had realized to a considerable extent the truth that the way of life is narrow and the way of destruction broad, and he did not think that the question of his everlasting peace was one which might be safely left to take care of itself, and that if he did not grievously trample on the commandments he would at least fare as well as his neighbours. The Lord tells him of a path by following which he might ensure the end he had in view; it was a proposal to allow of a barter (so to speak) in this particular case, of present wealth and ease for the promised treasure of heaven. And the great moral of the story is this, that the young man would not make the exchange.
II. Let us take the story as a proof that it is possible for a man to have treasure in heaven promised to him on the condition of his making the sacrifice of all his earthly wealth, and of the offer being refused. And this fact may serve as an answer to those who have objected to the Christian religion, as letting down the character of virtue by assigning rewards for the practice of it. The fear of those being bribed into holiness by the same hope of gain in heaven who would otherwise have been content to lead unholy lives, is a fear which philosophers may talk about, but for which common life will not give any colour or ground.
III. We do need something more than the mere hope of reward to enable us to do any great Christian act, and the religion of Christ does supply such a motive, and the New Testament represents the Apostles as acting upon that motive. If you inquire what the principle was which made the Apostles what they were, you can have no doubt in giving as an answer that it was the "constraining love of Christ."
Bishop Harvey Goodwin, Parish Sermons,3rd series, p. 198.
References: Matthew 19:16. Spurgeon, Evening by Evening,p. 154.Matthew 19:16. to Matthew 20:16. H. Wace, Expositor,2nd series, vol. i., p. 401.