Albert Barnes Commentary 1 Samuel 10:12

"And one of the same place answered and said, And who is their father? Therefore it became a proverb, Is Saul also among the prophets?" — 1 Samuel 10:12 (ASV)

But who is their father? — This is a very obscure phrase. If by “father” is intended the head or leader (compare 1 Chronicles 25:6; 2 Kings 2:12) of the prophets, the question means: “What kind of leader can they have to admit such a person as Saul into the company?” Some versions read “Who is his father?” in the sense: “Who would have expected Kish to have a son among the prophets?” .