וְאִם־לֹ֤א תַשְׁלִים֙ עִמָּ֔ךְ וְעָשְׂתָ֥ה עִמְּךָ֖ מִלְחָמָ֑ה וְצַרְתָּ֖ עָלֶֽיהָּ׃
And if it will make no peace with thee, but will make war against thee, then thou shalt besiege it.
Read kabbalistic (mystical) interpretation of Deuteronomy 20:12: and classical mystical sources.