Rich young man

(Matthew 19:16-26 [KJV])
 [16] And, behold, one came and said unto him, Good Master, what good thing shall I do, that I may have eternal life?
 [17] And he said unto him, Why callest thou me good? there is none good but one, that is, God: but if thou wilt enter into life, keep the commandments.
 [18] He saith unto him, Which? Jesus said, Thou shalt do no murder, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness,
 [19] Honour thy father and thy mother: and, Thou shalt love thy neighbour as thyself.
 [20] The young man saith unto him, All these things have I kept from my youth up: what lack I yet?
 [21] Jesus said unto him, If thou wilt be perfect, go and sell that thou hast, and give to the poor, and thou shalt have treasure in heaven: and come and follow me.
 [22] But when the young man heard that saying, he went away sorrowful: for he had great possessions.
 [23] Then said Jesus unto his disciples, Verily I say unto you, That a rich man shall hardly enter into the kingdom of heaven.
 [24] And again I say unto you, It is easier for a camel to go through the eye of a needle, than for a rich man to enter into the kingdom of God.
 [25] When his disciples heard it, they were exceedingly amazed, saying, Who then can be saved?
 [26] But Jesus beheld them, and said unto them, With men this is impossible; but with God all things are possible.

Why did Jesus answer the way he did towards the young rich man?

Well you see those who were saved in the gospels they addressed Jesus as Lord not good master.

Why is this important.

Because anyone could see that Jesus seemed to be a good person since Jesus was healing people and Jesus had apprentices which a master has.

You see the rich young man did not believe. I believe Jesus knew that and this is also why the rich young man addressed him as good master rather than Lord.