וַֽיִּסְפְּדוּ֙ וַיִּבְכּ֔וּ וַיָּצֻ֖מוּ עַד־הָעָ֑רֶב עַל־שָׁא֞וּל וְעַל־יְהוֹנָתָ֣ן בְּנ֗וֹ וְעַל־עַ֤ם יְהוָה֙ וְעַל־בֵּ֣ית יִשְׂרָאֵ֔ל כִּ֥י נָפְל֖וּ בֶּחָֽרֶב׃ (ס)
And they wailed, and wept, and fasted until even, for Saul, and for Jonathan his son, and for the people of the LORD, and for the house of Israel; because they were fallen by the sword.
Read halakhic rulings (Jewish law) on II Samuel 1:12: and classical halakhic sources.