Who hath cut Rahab and wounded the dragon? What does this mean? Reynolds and Sjodahl clarified that Rahab represents Egypt (Commentary on the Book of Mormon, vol. 1, p. 290) and Ezek. 29:3 refers to Pharaoh as 'the great dragon.'
Therefore, we may paraphrase this passage as follows: "Art thou not he (the Great Jehovah) who hath cut off Egypt, and wounded Pharaoh? Art thou not he who hath dried the red sea, the waters of the great deep; that hath made the depths of the red sea a way for the ransomed children of Israel to pass over?"
This famous scriptural event is symbolic in many ways. The Egyptian armies were the most powerful military force on the face of the earth at the time that Moses confronted them. Still, the power of the Lord was strong enough to destroy them and save his people. This event will be repeated in the redemption of Zion and Jerusalem. In that day, the power of the Lord will rest with the saints to such a degree that 'it shall be said among the wicked; Let us not go up to battle against Zion, for the inhabitants of Zion are terrible; wherefore we cannot stand.' (DC 45:70) Similarly, Jerusalem will be saved from the fiercest army ever assembled in the history of the world (Rev. 9:16), and a careful review of the plagues listed in Revelation shows a striking similarity to the plagues of Egypt (compare Ex. 7-9 to Rev. 8-9). Therefore, when we think of the triumph of the children of Israel over the power of Pharaoh, we should see the latter-day symbolism. The power of the Lord was wielded on behalf his people then, and that same power will be wielded again in just as dramatic a fashion.