Jonathan (Hebrew: יְהוֹנָתָן Yəhōnāṯān or Yehonatan; or יוֹנָתָן Yonatan) is a heroic figure in 1 Samuel in the Hebrew Bible. He was the eldest son of King Saul and close friend of King David. Like his father, he was a man of great strength and swiftness (2 Samuel 1:23), and excelled in archery and slinging (2 Samuel 1:22 - 1 Chronicles 12:2).
Jonathan first appears in the biblical narrative as the victor of Geba, a Philistine stronghold (1 Samuel 13), while in the following chapter he carries out a lone attack on another Philistine garrison, demonstrating his "prowess and courage as a warrior." However, he eats honey without knowing that his father had said, "Cursed be any man who eats food before evening comes" (1 Samuel 14:24). Saul means to put Jonathan to death because of this, but relents when the soldiers protest (1 Samuel 14:45).
The story of David and Jonathan is introduced in chapter 18, where it says that "Jonathan became one in spirit with David, and he loved him as himself" (verse 1). Jonathan helps David escape from Saul, and asks him to show kindness to his family (1 Samuel 20:14-15), which indicates that Jonathan recognizes David as the future king.
Saul suspects that Jonathan is colluding with David, who he believes is conspiring to overthrow him. Saul insults Jonathan calling him the "...son of a perverse and rebellious woman!" in 1 Samuel 20:30. While this is an "idiom of insult directed at Jonathan", some scholars see in this verse support for the theory that Ahinoam, the wife of Saul was also the wife of David. Jon Levenson and Baruch Halpern suggest that the phrase "to the shame of your mother's nakedness" suggests "David's theft of Saul's wife". Saul even goes so far as to attempt to kill Jonathan by throwing a javelin at him during a fit of paranoid rage (1 Sam. 20:33).