Mark 7:19
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.) — the anatomical argument: food enters the digestive system, not the heart — the seat of moral reality. The heart is where defilement originates (verse 21); the stomach is not. Mark's parenthetical in saying this, Jesus declared all foods clean is a retrospective theological application of the principle to the dietary laws — the application that Peter will need a vision to grasp (Acts 10) and that will reshape early Christianity's relationship to Gentiles.