Scripture often refers to the sea as an image of many troubles and hardships. Here Yahweh speaks of himself accompanying the people to help them go through these afflictions. Alternate translation: "I will go with them and help them as they go through their many afflictions" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here to "strike" the waves is an idiom that means he will stop the waves from forming. Stopping the afflictions of his people is spoken of as calming the waves of that sea. Alternate translation: "I will cause the waves of that sea of affliction to stop" (See: [[rc://en/ta/man/translate/figs-idiom]] and [[rc://en/ta/man/translate/figs-metaphor]])
Here "the majesty of Assyria" probably refers to the Assyrian army. Alternate translation: "I will destroy Assyria's proud army" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "the scepter of Egypt" refers to the political power of Egypt. Alternate translation: "the power of Egypt to rule other nations will end" (See: [[rc://en/ta/man/translate/figs-metonymy]])