וַיַּֽעֲזָר־לוֹ֙ אֲבִישַׁ֣י בֶּן־צְרוּיָ֔ה וַיַּ֥ךְ אֶת־הַפְּלִשְׁתִּ֖י וַיְמִיתֵ֑הוּ אָ֣ז נִשְׁבְּעוּ֩ אַנְשֵׁי־דָוִ֨ד ל֜וֹ לֵאמֹ֗ר לֹא־תֵצֵ֨א ע֤וֹד אִתָּ֙נוּ֙ לַמִּלְחָמָ֔ה וְלֹ֥א תְכַבֶּ֖ה אֶת־נֵ֥ר יִשְׂרָאֵֽל׃ (פ)
But Abishai the son of Zeruiah succoured him, and smote the Philistine, and killed him. Then the men of David swore unto him, saying: ‘Thou shalt go no more out with us to battle, that thou quench not the lamp of Israel.’
Read kabbalistic (mystical) interpretation of II Samuel 21:17: and classical mystical sources.