וַיֹּ֣אמֶר דָּוִ֔ד אֶל־הַנַּ֖עַר הַמַּגִּ֣יד ל֑וֹ אֵ֣יךְ יָדַ֔עְתָּ כִּי־מֵ֥ת שָׁא֖וּל וִיהֽוֹנָתָ֥ן בְּנֽוֹ׃
And David said unto the young man that told him: ‘How knowest thou that Saul and Jonathan his son are dead?’
Read midrashic interpretation of II Samuel 1:5: and classical rabbinic exegesis.