“For men indeed swear by the greater, and an oath for confirmation is for them an end of all dispute. Thus God, determining to show more abundantly to the heirs of promise the immutability of His counsel, confirmed it by an oath” (Hebrews 6:16-17).
The act of swearing an oath to verify the truth of a statement or commitment to a course of action is a practice that takes many forms. For instance, we place legal witnesses “under oath” when giving testimony in court. We also have the example of those government officials, law enforcement officers, and other formal authorities who are “sworn into” their various ranks of service. However, these contemporary oaths differ greatly from their ancient counterparts.
For example, some Old Testament contracts and legal agreements were formalized through a ceremony that involved the death of one or more animals. The parties involved in ratifying an agreement cut each animal in half and placed the halves opposite to one another on the ground. Both parties then proceeded to walk between the pieces of the sacrificed animals. We can find a detailed example of this type of oath in Genesis chapter fifteen.
While this practice may seem barbarous to modern-day audiences, it communicated something that is easy to understand. This ceremony declared that if either side failed to uphold the terms of their agreement, the guilty party would be subject to the same fate as the animal that had been sacrificed.
We can find another type of ancient oath in Genesis chapter 24…
“[Abraham] said to the chief servant in his household, the one in charge of all that he had, ‘Put your hand under my thigh. I want you to swear by the Lord, the God of heaven and the God of earth, that you will not get a wife for my son from the daughters of the Canaanites, among whom I am living, but will go to my country and my own relatives and get a wife for my son Isaac'” (Genesis 24:2-4).
Abraham was so determined to find the right marriage partner for Isaac that he told his servant, “Put your hand under my thigh… (and) swear…” It has been suggested that this action means, “May my descendants take action against you if you fail to fulfill this oath.”
Unlike fallible human beings, God’s truthful and unchanging nature means He has no need to swear an oath. Nevertheless, “God also bound himself with an oath, so that those who received the promise could be perfectly sure that he would never change his mind” (NLT). We’ll consider the immutability of that promise next.