Above all, be careful what you think.
Jesus rattled the Jewish dietary cage when he said their “kosher” regulations had things backward: it’s not what goes into your stomach that corrupts but what goes into your mind.
It is the thought-life that defiles you. For from within, out of a person’s heart, come evil thoughts, sexual immorality, theft, murder, adultery, greed, wickedness, deceit, eagerness for lustful pleasure, envy, slander, pride, and foolishness. All these vile things come from within (Mk 7:20–23).
Spiritual contamination has nothing to do with what you spoon into your mouth, and everything to do with what you shovel into your mind.
“Above all,” wrote Solomon, “be careful what you think because your thoughts control your life” (Prv 4:23).
Today’s thoughts become tomorrow’s doings.