What is the Difference Between "Swear" and "Affirm" in an Oath?

Many oaths of office contain the text “I, ________ do swear (or affirm)...” When people take such an oath, they have the option of choosing between swearing and affirming, depending on the region where they live. When someone opts to affirm rather than to swear, the oath is more properly known as an affirmation. The difference between the two may seem subtle, but to some people, it is extremely important. It also continues to be an issue in some regions of the world.

Some Christians prefer to say “I affirm” rather than “I swear” because of a section in the Book of Matthew, in which Christ is said to have specifically advised His followers against swearing. Quakers, Mennonites, and members of some other Christian sects choose to not to swear because they believe firmly in telling the truth at all times, and feel that swearing to tell the truth goes against their religious values because it suggests that they might lie at other times.

People have been taking oaths for thousands of years, and the issue of affirming as opposed to swearing only really began to arise in the 1600s, when the Christian church branched out into a multitude of differing sects, and some bold atheists began to be more outspoken about their beliefs. Quakers especially found themselves persecuted for refusing to swear, and they were barred from public office and unable to testify in court as a result of their religious beliefs.

The alternative of an affirmation began to be suggested, with one of the first laws explicitly allowing this appearing in England. Over time, the convention of offering both choices began to be quite common, and the language “swear (or affirm)” was written directly into the text of many oaths of office. Affirmation is not an option all over the world, however, and this can become an issue when someone of a cultural or religious background that forbids swearing is obliged to testify in a country where affirmations are not accepted.

There are differing conventions about the decision to affirm rather than to swear. In some regions, it is assumed that someone will swear, and when the text of an oath is read out loud, only that part may be mentioned. If someone wants to make an affirmation rather than an oath in these cases, he or she must inform the person administering the affirmation before it takes place. In some regions, someone must also provide grounds for preferring an affirmation. For example, a Quaker would say that he or she is opposed to swearing for religious reasons.