Vahrenhorst, Martin. "Chapter Sixteen: The Presence and Absence of a Prohibition of Oath in James, Matthew, and the Didache and Its significance for Contextualization." in Van de Sandt, Huub & Zangenberg, Jürgen K. (editors). Matthew, James, and Didache: Three Related Documents in their Jewish and Christian Settings." Atlanta, GA: Society of Biblical Literature, 2008, 361-377.
Vahrenhorst notes the scholarly opinions about Matthew shifting toward the writing coming from a community which is first Christian but with Jewish elements, rather than one which is first Jewish but with Christian elements (Vahrenhorst 2008, 362). Just the same, he sees in Matthew, especially 5:17-20, a solid allegiance to the Torah, with a typical rabbinic desire to apply the principles to everyday life.
The nature of oaths and vows in different Jewish contexts is a matter of substantial debate (Vahrenhorst 2008, 365). Because of this, Vahrenhorst considers a study of oaths in Matthew, James, and the Didache likely to be fruitful. The prohibition of swearing an oath using God's name serves to guard against asserting wrong values to God or claiming He is responsible for our failure to keep a promise (Vahrenhorst 2008, 365). Yet it is necessary to make firm promises. Therefore, Jewish writings tend to suggest promises, calling upon parents or other authorities (Vahrenhorst 2008, 366). Vahrenhorst notes that there was a distinction made between swearing an oath and making a vow, which would still express a commitment to an action but would avoid profaning God's name (Vahrenhorst 2008, 366-367).
Matthew has three significant passages regarding oaths. In 5:33-37, Matthew records Jesus as teaching that vows made to the Lord are binding (Vahrenhorst 2008, 368). To avoid breaking a vow, one should avoid making vows. In effect, the logical implication of involving God in a vow is that God will keep the promise if the promiser fails to do so. The same counsel appears in Matthew 23:16-22, where the Jewish leaders are identified as "blind" (Vahrenhorst 2008, 369). In the other, brief, passage, Peter denies knowing Jesus, using an oath. This is clearly seen as a negative response.
The Didache contains only one saying, in 2:2, about oaths, prohibiting those which are false (Vahrenhorst 2008, 371). However, the Torah is not mentioned specifically as an authority for the moral views of the Didache. Just the same, the moral authority seems to be drawn from Old Testament passages (Vahrenhorst 2008, 372). There are widely recognized halakhic elements in the Didache, which show a positive relationship with Jewish thought (Vahrenhorst 2008, 373).
James 5:12 makes a clear prohibition of oaths, but with no explanation (Vahrenhorst 2008, 375). This is consistent with the concern James shows with the ethics surrounding speech. One's life is to be consistent, including a confluence of speech and actions.