'Oath' in the Bible

Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne;

And Paul, after waiting some days, went away from the brothers and went by ship to Syria, Priscilla and Aquila being with him; and he had had his hair cut off in Cenchrea, for he had taken an oath.

Do this, then, which we say to you: We have four men who have taken an oath;

Go with these, and make yourself clean with them, and make the necessary payments for them, so that they may be free from their oath: and everyone will see that the statements made about you are not true, but that you put yourself under rule, and keep the law.

In the morning, the Jewish leaders formed a conspiracy and took an oath not to eat or drink anything before they had killed Paul.

and they were more than forty who made this conspiracy by oath,

They went to the high priests and elders and said, "We have taken a solemn oath not to taste any food before we have killed Paul.

But do not thou yield unto them: for there lie in wait for him of them more than forty men, which have bound themselves with an oath, that they will neither eat nor drink till they have killed him: and now are they ready, looking for a promise from thee.