Graydon Snyder and Kenneth Shaffer, in their book Texts in Transit II, write that "From their beginnings the Brethren have objected to the practice of swearing an oath as proof that one is telling the truth or as assurance that one will abide by an agreement."
Alexander Mack writes in his Rights and Ordinances (1715) that a government can depend more upon citizens who affirm with yes and deny with no than upon citizens who insist upon swearing oaths. Refusal to swear the oath, according to Mack, is "in accordance with the teaching of Christ."
Snyder and Shaffer write that during the American Revolution the oath of allegiance required by state governments presented problems for Brethren. These problems, however, had more to do with the Brethren beliefs concerning the relationship of church and state than with the Brethren refusal to swear an oath, since the law allowed a person to affirm the oath instead of swearing. Even so, in 1785, only two years after the revolution, Annual Meeting specifically referred to Matthew 5:37 when dealing with the issue of oaths: "As to the swearing of oaths, we believe the word of Christ, that in all things which we are to testify, we shall testify what is yea, or what is true with yea, and what is nay, or not true with nay; for whatsoever is more than these cometh of evil."