The answer is: Oaths

Matt 5:36

When Jesus said one cannot make a hair on their head black or white, he's really diving into a profound lesson on the futility of elaborate oaths. In Matthew 5:36, he's essentially calling out the human tendency to attach importance to our words, suggesting we can control outcomes through promises. "To swear by your head," he states, is quite pointless, for we cannot change our natural makeup. This reflects the notion that life is intrinsically uncertain and unpredictable.

Fun trivia: Did you know that hair actually does have a complex biological makeup? Each strand's color is determined by genetic factors along with melanin levels. In biblical times, color symbolism was emblematic; think of how white represented purity or righteousness while black could denote hidden mysteries or darkness. Jesus' point wasn’t just formal—it encouraged adherence to truth over bravado about one's commitments.

Echoing this theme is James 5:12, where a similar warning appears about swearing oaths—highlighting that one’s integrity should be enough without needing embellishments. Thus, the focus becomes on honest speech and authenticity, encouraging all to consider how the simplest statements can carry the deepest weight, turning casual conversations into declarations of sincerity. So, next time you promise something—to yourself or another—remember, it's often the sincerity behind those words that holds real power, not the theatrical flourishes.