Moby Dick

by Herman Melville

“Oh! thou clear spirit of clear fire, whom on these seas I as Persian once did worship, till in the sacramental act so burned by thee, that to this hour I bear the scar; I now know thee, thou clear spirit, and I now know that thy right worship is defiance. To neither love nor reverence wilt thou be kind; and e’en for hate thou canst but kill; and all are killed. No fearless fool now fronts thee. I own thy speechless, placeless power; but to the last gasp of my earthquake life will dispute its unconditional, unintegral mastery in me. In the midst of the personified impersonal, a personality stands here. Though but a point at best; whenceso’er I came; whereso’er I go; yet while I earthly live, the queenly personality lives in me, and feels her royal rights. But war is pain, and hate is woe. Come in thy lowest form of love, and I will kneel and kiss thee; but at thy highest, come as mere supernal power; and though thou launchest navies of full-freighted worlds, there’s that in here that still remains indifferent. Oh, thou clear spirit, of thy fire thou madest me, and like a true child of fire, I breathe it back to thee.”

At this moment in the story, the ship is in a tempest and Ahab holds the chain at the end of the lightning rod. Given the description of the scar initially, it seems likely he was scarred by a lightning strike running down a similar chain in an earlier storm. Also note he says "as Persian once did worship." Worshipping like a Persian or being of Persian background.