Silsilat al-Ahadith al-Sahihah

Sayyiduna Ka'b bin Malik (may Allah be pleased with him) said to the Prophet (peace and blessings be upon him): Indeed, whatever Allah Almighty has revealed regarding poetry, He has revealed (so what is your opinion about poetry now?). The Prophet (peace and blessings be upon him) said: "Verily, the believer strives with both his sword and his tongue, and by the One in Whose hand is my soul! Whatever you say to them with your tongue (that is, by condemning the enemies through poetry) affects them like a shower of arrows."