It is an issue of perennial controversy between Catholics and Protestants: faith and good works (or “faith versus good works,” with its built-in prejudicial notion that the two are opposed).
Saint Matthew’s melancholy account of the rich young man who approaches our Lord asking what he must do to have life everlasting would have been an excellent proof-text for the Protestant position in the matter — would have been, that is, had the episode gone very differently. If, when the rich young man approaches Our Lord with the question, “Good master, what good shall I do that I may have life everlasting?,” Jesus had answered: “Do? You need do nothing, young man! All you need is the gift of faith, for we account a man to be saved by faith alone without the works of the Law.”
That would have been the answer of the Lutheran savior, or the Calvinist one.
But the real Jesus does not reply that way, not at all. Instead, He specifically tells the young man, “But if thou wilt enter into life, keep the commandments.” Then, beyond the commandments, he offers the man something higher: the life of the counsels: “If thou wilt be perfect, go sell what thou hast, and give to the poor, and thou shalt have treasure in heaven: and come follow me.” (Movingly, the parallel passage in Saint Mark’s Gospel adds these words of preface to the Savior’s invitation: “And Jesus looking on him, loved him, and said to him….”)
But let us return to Jesus’ declaration: “… if thou wilt enter into life, keep the commandments.” The conclusion is inescapable. Keeping the commandments (which Jesus elsewhere says is proof of our love for Him) is a condition for salvation. Jesus clearly missed His opportunity to be the Christ of Martin Luther and John Calvin.
Calvin, however, would have none of it! Here is Cornelius a Lapide, in his Great Commentary, taking the Swiss would-be-reformer to task for his mangled exegesis of the sacred page:
Calvin foolishly and just as impiously thinks that Christ is here addressing the young man ironically, because he trusted in the works of the Law; inasmuch as there is no road to heaven through the keeping of the commandments, since that is impossible for men; but by faith. There are here as many errors and heresies, yea blasphemies, as there are words. It is diametrically opposed to what Christ means and declares, and is at bottom subversive of it. Hence it is plain that Calvin was led, not by the Spirit of Christ but of Antichrist. See among Catholics, Maldonatus and Adam Gontzen, who write with the express object of refuting Calvin and the Protestants. Let us go on to speak of what will be of more use to the Orthodox [i.e. right-believing Catholics]. Christ here teaches that it is not faith alone that justifies and saves, but good works are also required, by which in fulfilling the law, we may obtain the reward of eternal life and glory, which has been promised by God to those who fulfill the law.
Below is the entire passage, from the Douay-Rheims translation. The King James Version is identical in the essential details relevant to this argument. Go here to find that translation, along with a host of other Protestant translations all a mere click away.
And behold one came and said to him: Good master, what good shall I do that I may have life everlasting? Who said to him: Why asketh thou me concerning good? One is good, God. But if thou wilt enter into life, keep the commandments. He said to him: Which? And Jesus said: Thou shalt do no murder, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness. Honour thy father and thy mother: and, Thou shalt love thy neighbour as thyself. The young man saith to him: All these I have kept from my youth, what is yet wanting to me? Jesus saith to him: If thou wilt be perfect, go sell what thou hast, and give to the poor, and thou shalt have treasure in heaven: and come follow me. And when the young man had heard this word, he went away sad: for he had great possessions. Then Jesus said to his disciples: Amen, I say to you, that a rich man shall hardly enter into the kingdom of heaven. And again I say to you: It is easier for a camel to pass through the eye of a needle, than for a rich man to enter into the kingdom of heaven. And when they had heard this, the disciples wondered very much, saying: Who then can be saved? And Jesus beholding, said to them: With men this is impossible: but with God all things are possible. [Matt. 19: 16-26]