'Swear' in the Bible

Therefore swear an oath here by God that you won't deal falsely with me, my sons, or my descendants. Just as I've dealt graciously with you, won't you do so with me and with the land in which you live as a foreigner?"

and said, "I have taken an oath to swear by myself," declares the LORD, "that since you have carried this out and have not withheld your only unique son,

My master made me swear this oath: "You are not to select a wife for my son from among the daughters of the Canaanites in this land where I live.

But Jacob insisted, "Swear it by an oath right now." So he swore an oath to him and sold his birthright to Jacob.