'Made a Vow' in the Bible

Paul stayed for a while longer, and then told the brothers and sisters goodbye and sailed for Syria; and he was accompanied by Priscilla and Aquila. At Cenchrea [the southeastern port of Corinth] he had his hair cut, because he was keeping a [Nazirite] vow [of abstention].

So, here is what we would like you to do: We have four men who have made a vow [i.e., a special promise to God].

When day was come, certain of the Jews gathered themselves together, and made a vow saying that they would neither eat nor drink till they had killed Paul.