The answer is: Oaths

Matt 5:36

In Matthew 5:36, when Jesus says you can't make one hair on your head black or white, he touches on the futility of swearing oaths. His point is about the limitations of human authority over creation; we can't alter something as basic as our hair's color with a mere word. What’s fascinating here is that this reflects a deeper principle of the natural order—people often underestimate the parameters of their power.

Interestingly, the Talmud, the central text of rabbinic Judaism, had intricate rules about oaths and swearing. The Jewish tradition placed immense importance on being truthful, so Jesus was echoing these sentiments, getting to the core of integrity, truthfulness, and the idea that what truly matters is one's character and words—not their ability to throw around solemn promises.

And did you know that in anatomy, the average person has about 100,000 to 150,000 hair strands on their head? That’s a lot of hair to manage! Just like our individual strands might seem unconcerned with their color or even with the larger topics of oaths, each person's actions and words carry their own weight in moral representation. Just as badgering someone with oaths can lead to harm, an unexamined life can cause one to misdirect their values, highlighting that according to this teaching, consistency and sincerity illustrate the essence of a true follower of goodness.