In Biblical Old Testament times the process of swearing by an oath was common practice. It was a way to assure another that you “gave them your word.” Unlike most situations today, your word was your bond. There was no signing of contracts with notaries involved, it was simply your word or oath, that sealed the deal. We can see this very clearly displayed from an incident in the Book of Mormon. In 1 Nephi chapter 4 the Lord commands Nephi to kill Laban so that they can retrieve the plates. Zoram, who was the servant of Laban, is tricked into getting the records and following Nephi out of town. Upon seeing his great mistake he contemplates going back to get help.
1 Nephi 4:31 And now I, Nephi, being a man large in stature, and also having received much strength of the Lord, therefore I did seize upon the servant of Laban, and held him, that he should not flee.
32 And it came to pass that I spake with him, that if he would hearken unto my words, as the Lord liveth, and as I live, even so that if he would hearken unto our words, we would spare his life.
33 And I spake unto him, even with an oath, that he need not fear; that he should be a free man like unto us if he would go down in the wilderness with us.
34 And I also spake unto him, saying: Surely the Lord hath commanded us to do this thing; and shall we not be diligent in keeping the commandments of the Lord? Therefore, if thou wilt go down into the wilderness to my father thou shalt have place with us.
35 And it came to pass that Zoram did take courage at the words which I spake. Now Zoram was the name of the servant; and he promised that he would go down into the wilderness unto our father. Yea, and he also made an oath unto us that he would tarry with us from that time forth.
36 Now we were desirous that he should tarry with us for this cause, that the Jews might not know concerning our flight into the wilderness, lest they should pursue us and destroy us.
37 And it came to pass that when Zoram had made an oath unto us, our fears did cease concerning him.
Even though an oath was fixed and sure, there were different levels of oaths. When they swore by an oath they would swear upon something that was important to them. For example, they would swear by their family, their life, or their Lord. The strongest oath was the one taken that was upon the Lord because it was of greatest value. The terminology would be something like, “I swear by my life that I will do this thing, and if I do not, then I would suffer my life to be taken as payment.”
Notice when Nephi made the oath to Zoram he used the words “as the Lord liveth, and as I live”. This terminology would have been the highest oath that could be given. Zoram’s fears completely left him upon hearing this oath, and he too entered into an oath that he would “tarry with them from that time forth.” Instantly all their “fears did cease concerning him.” The oath, or word, was unshakable.
When it comes to the Oath that is involved in the Oath and Covenant of the priesthood, God is the one swearing the oath. It is also important to note that “He swore by himself”.
Genesis 14:30 For God having sworn unto Enoch and unto his seed with an oath by himself;
This is the highest form of an oath that could be given, God swearing by God. This is to let us, as His children know that this priesthood power is “sure”. How blessed we are to have this priesthood “after the order of the Son of God” with the promises that it brings.