וַיֹּ֣אמֶר דָּוִ֔יד כָּל־מַכֵּ֤ה יְבוּסִי֙ בָּרִ֣אשׁוֹנָ֔ה יִהְיֶ֥ה לְרֹ֖אשׁ וּלְשָׂ֑ר וַיַּ֧עַל בָּרִאשׁוֹנָ֛ה יוֹאָ֥ב בֶּן־צְרוּיָ֖ה וַיְהִ֥י לְרֹֽאשׁ׃
And David said: ‘Whosoever smiteth the Jebusites first shall be chief and captain.’ And Joab the son of Zeruiah went up first, and was made chief.
Read kabbalistic (mystical) interpretation of I Chronicles 11:6: and classical mystical sources.