וַיְהִ֣י ׀ בַּיּ֣וֹם הַשְּׁלִישִׁ֗י וְהִנֵּה֩ אִ֨ישׁ בָּ֤א מִן־הַֽמַּחֲנֶה֙ מֵעִ֣ם שָׁא֔וּל וּבְגָדָ֣יו קְרֻעִ֔ים וַאֲדָמָ֖ה עַל־רֹאשׁ֑וֹ וַיְהִי֙ בְּבֹא֣וֹ אֶל־דָּוִ֔ד וַיִּפֹּ֥ל אַ֖רְצָה וַיִּשְׁתָּֽחוּ׃
it came even to pass on the third day, that, behold, a man came out of the camp from Saul with his clothes rent, and earth upon his head; and so it was, when he came to David, that he fell to the earth, and prostrated himself.
Rashi on II Samuel
Behold a man came from the camp. The Pesikta1Pesikta Rabosi 12,9. brings an opinion that this man is Doeig,2Doeig HaEdomi is first mentioned in Shmuel 1,21:8. but the explanation is indefensible in my heart.3It is clear from Shmuel 1, 22:18 that Shaul knew Doeig. Therefore, if in fact this man is Doeig, why did Shaul have to ask later in v. 8, “Who are you?” (Seder Hadoros, p. 102).