What is the difference? We are always asked this question, so let me help to shed some light on the subject. An oath is a verbal promise to tell the truth while holding the Bible. This is normally seen when a witness is called to give evidence in a criminal proceeding, the first thing he or she is required to do is to take an oath or affirmation. This person is merely stating that they will tell the truth to the court. They will raise their right hand and swear to tell the truth and only the truth.
On the other hand, an affirmation is a verbal, solemn and formal declaration, which is made in place of an oath. Individuals can choose to make an affirmation rather than an oath. An affirmation has the same effect as an oath but doe not use a religious text.
Example: Oath: I swear to God that the evidence I am about to give is the truth, the whole truth and nothing but the truth.
Affirmation: I solemnly declare and affirm that the evidence I am about to give will be the truth, the whole truth and nothing but the truth.