The problem is that the synoptic gospels do not regard Jesus as God, but as being a great teacher, prophet and Jew, and also the man to lead them into the kingdom they wanted, whatever they thought that to be. They were not really clear on what it was, either, because Luke 17 says
 And when he was demanded of the Pharisees, when the kingdom of God should come, he answered them and said, The kingdom of God cometh not with observation:
 Neither shall they say, Lo here! or, lo there! for, behold, the kingdom of God is within you.
Some conceived of it as being a mental kingdom that would come, when enough of them were right with God, through the awesome understanding of Jesus. I'm avoiding using the word "Messiah", because nobody knows what it means. Nobody even knows what the Jews thought the Messiah was supposed to do; but the idea that he was supposed to create a kingdom on Earth, in their time, is consistent with Jewish interpretation of prophecy. At the time the synoptic gospels started being written, it would still have seemed like the new interpretation of Judaism, (which still didn't have a name), could bring about world peace. However, as it dragged on, it would need reinterpretation, and counter polemic.
This problem of Jesus not being God, and actually denying being "good" is not the worst problem of the schism between the synoptics and John/Paul.
 And Jesus said unto him, Why callest thou me good? none is good, save one, that is, God.
It's in all three synoptic gospels. Nothing could be more blatant than that. It's possibly even put there for polemic purposes, against those who would worship Jesus. The Jesus of the synoptic paints a clear picture that you are supposed to get into heaven by works and perfection.