Jesus called the crowd to him and said, “Listen to me, everyone, and understand this. Nothing outside a person can defile them by going into them. Rather, it is what comes out of a person that defiles them.” After he had left the crowd and entered the house, his disciples asked him about this parable. “Are you so dull?” he asked. “Don’t you see that nothing that enters a person from the outside can defile them? For it doesn’t go into their heart but into their stomach, and then out of the body.” (In saying this, Jesus declared all foods clean.) He went on: “What comes out of a person is what defiles them. For it is from within, out of a person’s heart, that evil thoughts come—sexual immorality, theft, murder, adultery, greed, malice, deceit, lewdness, envy, slander, arrogance and folly. All these evils come from inside and defile a person.”
-- Mark 7: 14-23
I was listening to the gospel via a website that not only provides various translations but audio for a few of them and caught this interesting passage. Why so? Check out that parenthetical, which is serious business -- it appears to do away with kosher rules. "Jesus" here is saying that all food are clean, a remarkable thing for a Jewish "rabbi" (as he is called more than once, though it sounds Jewish to our ears). An earlier comment where he said Sabbath is made for man, not man for the Sabbath is also notable. But, this is particularly so.
Of course, things look a bit different if we realize the parenthetical is a later gloss, not necessarily something Jesus himself said. Mark, the earliest gospel (it might be the case that parts of the Thomas gospel was collected earlier), still was written long after Jesus' time on earth. A newspaper article today often has questionable glosses placed on certain facts. An ideological publication only more so. Imagine if they were talking about things that took place decades ago with only word of mouth and perhaps some true believer notes to rely on? These asides should be taken with that in mind.
It also is notable to look at how the same concept is dealt with in other places in the New Testament. Peter had a crisis of faith on the question of eating "impure" foods or eating with Gentiles, Acts holding that a vision led him to decide it okay. Nonetheless, food along with other matters were still a matter of debate enough to have to be settled in a special council (Acts 15), which decided that "You are to abstain from food sacrificed to idols, from blood, from the meat of strangled animals and from sexual immorality." Paul, writing earlier, also noted Peter's concerns, noting he was pressured by James (Jesus' brother) not to eat with Gentiles.
This would all be strange if Jesus himself made clear that all food was clean. Was even James so "dull" on this matter? Possibly. On the other hand, we might have to read between the lines. (Jesus/actual practice) to Paul to Mark to Luke (the assumed writer of Acts) acted in different times and contexts. The first disciples still saw themselves as Jews, following Jewish dietary rules, even if exactly how this should be done was open to debate. In time, "Christianity" became more and more not a Jewish religion. Mark himself was writing as the fall of the Jewish rebellion was still crisp in the memory of his readers. James had been martyred at least a decade earlier. Luke tried to find a middle path -- Peter and Paul in effect on equal footing. The dietary tidbit is a flag here.
Such things easily can be missed, but make the reading particularly interesting.