וַֽיִּקְרְאוּ֙ בְּק֣וֹל גָּד֔וֹל וַיִּתְגֹּֽדְדוּ֙ כְּמִשְׁפָּטָ֔ם בַּחֲרָב֖וֹת וּבָֽרְמָחִ֑ים עַד־שְׁפָךְ־דָּ֖ם עֲלֵיהֶֽם׃
And they cried aloud, and cut themselves after their manner with swords and lances, till the blood gushed out upon them.
Rashi on I Kings
And they gashed themselves. An expression of tearing the flesh with an instrument, for such was their custom.