The answer is: Oaths

Matt 5:36

In this part of the Sermon on the Mount, Jesus teaches about the futility and seriousness of oaths. He emphasized that people often use oaths to add weight to their words, perhaps indicating a lack of trustworthiness in their everyday speech. When he stated that you can’t make one hair on your head black or white, he was drawing attention to the limitations of human control. It reminds us that we often want to control our image and trustworthiness by embellishing our words, yet there are fundamental truths about our existence that we cannot alter—how we can’t even selectively change the color of our hair!

This teaching ties back beautifully with themes found throughout the scriptures that advocate for honesty and integrity. In Proverbs, for example, there's a strong push toward truthfulness, declaring that “the Lord detests lying lips.” It highlights an important echo in wisdom literature where simplicity in speech is held in lofty regard, aligning with what Jesus testified about respecting the divine equality of all humanity. Additionally, the call to be people of integrity accompanied by simple and trustworthy "yes" or "no" reassures us that actions speak just as eloquently as words do.

Interesting to note is that the tradition of swearing oaths often goes back to ancient practices, but these words from Jesus heralded a movement towards inward righteousness that prioritizes character over ceremonial practice, resonating through centuries of discussions on ethics and personal responsibility!