וַיֵּצְאוּ֙ בְּנֵ֣י עַמּ֔וֹן וַיַּֽעַרְכ֥וּ מִלְחָמָ֖ה פֶּ֣תַח הָעִ֑יר וְהַמְּלָכִ֣ים אֲשֶׁר־בָּ֔אוּ לְבַדָּ֖ם בַּשָּׂדֶֽה׃
And the children of Ammon came out and put the battle in array at the gate of the city; and the kings that were come were by themselves in the field.
Read midrashic interpretation of I Chronicles 19:9: and classical rabbinic exegesis.