Notes on the Bible, by Albert Barnes, , at sacred-texts.com
1 Kings (1 Samuel) 20:1
While Saul was under the constraining influence of the spirit of prophecy, David escaped from Naioth, and, probably by Samuel's advice, returned to Saul's court to commune with Jonathan. Nothing could be a better evidence of his innocence than thus putting himself in Jonathan's power. Perhaps something passed between Samuel and Saul on the subject, since it appears from Sa1 20:5, Sa1 20:25, Sa1 20:27, that Saul expected David at the feast of the new moon.
1 Kings (1 Samuel) 20:2
It is not so - Jonathan's unwillingness to believe evil of his father is one of the many admirable traits in his character.
1 Kings (1 Samuel) 20:3
And David sware moreover - Rather, "yet again." He met Jonathan's denial by repeating his statement and confirming it with an oath.
1 Kings (1 Samuel) 20:5
The new moon, or beginning of each month, was celebrated with especial sacrifices and blowing of trumpets (marginal references.) The feast was kept with great solemnity as "a day of gladness," and we may presume that the "peace offerings" offered on the occasion furnished the tables of those that offered.
1 Kings (1 Samuel) 20:14
The general meaning is: Jonathan had a presentiment, doubtless from God, that David would be established upon the throne. By God's mercy he had the comfort, which he well deserved, of knowing that his own posterity would receive kindness at David's hand (see the marginal references).
1 Kings (1 Samuel) 20:19
The stone Ezel - It is not mentioned elsewhere, except possibly in Sa1 20:41, where see the note.
1 Kings (1 Samuel) 20:26
He is not clean - The new moon being a religious feast, and the meat to be eaten being peace-offerings, no one could assist at the feast who had any ceremonial uncleanness upon him (marginal references).
1 Kings (1 Samuel) 20:30
The greatest insult and most stinging reproach that can be cast upon an Oriental is to reproach his parents or ancestors (see Job 30:8). Saul means to intimate that Jonathan was stubborn from his mother's womb.
1 Kings (1 Samuel) 20:41
A place toward the south - An unintelligible description; one expects a repetition of the description of David's hiding-place in Sa1 20:19. The Septuagint in both places has "argab," a word meaning a "heap of stones." If this be the true reading, David's hiding-place was either a natural cavernous rock which was called "Argab," or some ruin of an ancient building, equally suited for a hiding-place.
Bowed himself three times - In token, doubtless, of his unshaken loyalty to Jonathan as the son of his king, as well as his friend; and in acknowledgment of Jonathan's power to kill him if he saw fit. (Compare Gen 33:3).
David exceeded - His affection for Jonathan, coupled with his sense of Saul's injustice and his own injured innocence, fully accounts for his strong emotion.
1 Kings (1 Samuel) 20:42
Jonathan went into the city - From which one may infer, what the after history also indicates, that Jonathan's filial duty and patriotism prevented a complete rupture with his father. Jonathan's conduct in this, as in everything, was most admirable.