It is quite possible to trap clergymen, as well as laymen, with the following question, because they are not always learned in the Old Testament.
"If David was the father of Solomon, and Joab was the son of Zeruiah, what relation was Zeruiah to Joab?"
Most persons give the answer that Zeruiah was the father of Joab, necessarily. That is not the correct answer. The trouble is that Zeruiah was a woman. And, of course, David and Solomon having nothing whatever to do with the case.