What does it mean to cut Rahab in pieces in Isaiah 51:9?

Answer

Most Bible readers know Rahab as the heroine of the battle of Jericho story (Joshua 2;6:22-25). But the name Rahab is also associated in the Bible with a mythical sea creature. In the original Hebrew, the spelling is slightly different: the Rahab of Jericho was רָחָב, while the Rahab of the sea was רַהַב. The difference is a cheit versus a hei as the middle letter.

Bible writers sometimes used the imagery of Rahab, a monster of chaos, as a derogatory representation of Egypt, as in Isaiah 51:9:

“Awake, awake, arm of the Lord,

clothe yourself with strength!

Awake, as in days gone by,

as in generations of old.

Was it not you who cut Rahab to pieces,

who pierced that monster through?”