Mark 10:18

‘And Jesus said to him, “Why do you call me good? None is good except one, even God.” '

Jesus gently asks him why he calls Him uniquely good. He was not by this denying His own goodness. That was not really the question at issue. He was rather asking the young man to think through what he meant by ‘goodness', and to recognise what quality was in his mind. For what he needed to realise was that as far as he was concerned that goodness that he was speaking about was unattainable, because it was a goodness that was only true of God. And the truth therefore was that no one could become good in that way, because only God is essentially good. In other words He was stressing that true goodness is something that is beyond men, because it is something innate, not earned, and He wanted the young man to recognise the fact. Thus for the young man to have suggested that even Jesus was good when he thought of Him as a mere prophet demonstrated the inadequacy of his thinking, for it revealed that he did not know what true goodness was. Indeed if he really did think that Jesus was truly good let him consider what the consequences of that thought would be. It would be to put Jesus on the divine side of reality. That this point is in Jesus' mind in the background (at least as far as Mark is concerned) comes out in the parallel verses in the chiasmus. For there too there is the veiled recognition that He is to be seen as unique and on the divine side of reality, for He speaks there of men making sacrifices ‘for His sake' and as a consequence receiving eternal life, not because they make the sacrifices, but because of their attitude of heart towards Him (Mark 10:29). Because they recognise His essential goodness they respond to Him with all their hearts, without reservations. The corollary of the thought is that no merely ‘good' Teacher could teach anyone how to be truly good, for such goodness had to be received from God.

There was unquestionably the implication here, to those who knew the truth, that in fact because He was Son of God He  was  intrinsically good, and He would not have denied such a level of goodness. But it is not the prominent idea in mind. What He wanted recognised was that to find goodness men must find God and that such goodness was not something for another to achieve, or that was achievable by men on earth. They could only become absorbed into His goodness. What the young man was seeking was therefore impossible. But how was He to make him realise the fact?