Of Blood Oaths and Sacred Vows

Why do we require Blood Oaths and Sacred Vows? Why isn’t a person’s word their bond? Why bring the body and holy into the covenant of our truth telling with others?

Why do we place more value in vows sworn on Bibles and other imbued relics than simply assuming one will tell the truth by default?

Is there an added potency to a claim when it is sworn “on my dead mother’s grave?” What is the purpose of secret handshakes, candlelight ceremonies and swearing in those who seek public service? Is our punishment more severe when blood oaths and sacred vows are broken?