Jonathan

Jonathan was the oldest son of King Saul, and he was David's best friend and brother-in-law, since David was married to Jonathan's sister Michal.

How David...Did Yet Escape The Dangers He Was In By The Affection And Care Of Jonathan
Flavius Josephus, first century historian and author of Antiquities of the Jews, profiled Jonathan and his relationship with David in this chapter.
Jonathan: The Faithful Friend
Explores the use of the life of Jonathan as a type of Jesus Christ.