'Swear' in the Bible

Then a man from the army informed [him] and said, "Your father made the army swear a solemn [oath], saying, 'Cursed be the man who eats food today,'" so the army [is] exhausted.

For as Yahweh lives, who delivers Israel, [I swear] that even if it [is] in Jonathan my son, {he will certainly die}!" But nobody from all the army answered him.

And Jonathan again made David swear an oath, because he loved him; for with the love of his soul he loved him.

So then, swear to me by Yahweh that you will not cut off my {descendants} after me and that you will not wipe out my name from my father's house."

So David asked him, "Will you take me down to this band [of raiders]?" He said, "Swear to me by God that you will not kill me and that you will not deliver me into my master's hand! Then I will take you down to this band."