The answer is: Oaths

Matt 5:36

When Jesus mentions that you can't change a hair's color—black or white—he's illustrating the limitations of human authority and control, particularly over something as trivial and natural as hair color. This mindset challenges the strongly rooted cultural practices of oaths prevalent in His time.

Jesus was highlighting that invoking oaths often led to deceptive and exaggerated claims. He stressed the importance of honesty in words alone, making it clear that it shouldn't take a promise to compel truth. Instead, let the soundness of your word suffice! Embracing integrity means that your “yes” should be honest as is; there’s no need for fancy promises—after all, you can’t get too caught up in grand gestures when life is better lived straightforwardly.

From a historical standpoint, people in many cultures would swear by something significant to lend weight to their promises, often becoming tangled in meticulous rules about which combinations worked best. Here, Jesus's wisdom echoes ancient teachings in the Hebrew Bible, where ‘bearing false witness’ ranks as a particularly grave offense (Exodus 20:16).

Interestingly, in Jewish literature, there's also talk about how even silly technicalities in oaths could lead people to escaping their moral duties. So, flipping that script, it seems Jesus wanted future generations to recognize their lives should embody the honest essence, not the embellished fabrications which might sadly mislead their life paths. Now that’s a thought-provoking idea for any society!