A more thorough explanation:

Definition: An oath against an oath is a situation where determining a crucial fact involves choosing between the credibility of two witnesses who have irreconcilable differences in their statements, and there is no other evidence to rely on. This is also known as a swearing match or a swearing contest.

Example: In a court case, two witnesses give conflicting statements about what they saw at the scene of a crime. One witness is a police officer, and the other is a convicted drug dealer. The fact-finder, such as a judge or jury, must decide which witness to believe based on their credibility. In this case, the police officer may be considered more reputable and trustworthy than the drug dealer, and their testimony may be given more weight.

Explanation: The example illustrates how an oath against an oath can occur in a legal setting, where the credibility of witnesses is crucial in determining the outcome of a case. The fact-finder must weigh the credibility of each witness and decide which testimony to believe, as there is no other evidence to rely on. This highlights the importance of credibility and honesty in giving testimony and taking oaths.