Exodus 14:9
But the Egyptians pursued after them, all the horses and chariots of Pharaoh, and his horsemen, and his army, and overtook them encamping by the sea, beside Pi-hahiroth, before Baal-zephon. But the Egyptians pursued after them, all the horses and chariots of Pharaoh, and his horsemen, and his army, and overtook them encamping by the sea, beside Pi-hahiroth, before Baal-zephon.
The pursuit did not begin at once, but after Israel had been gone some days, when word was brought to Pharaoh that they had fled and would never return to serve him again. It was after the judgments had ceased and the Egyptians had buried their dead that Pharaoh repented of letting them go. The Egyptians then bitterly regretted freeing Israel from serving them, mourning their departure as a very great loss of service.
The pursuing force was Pharaoh's whole army, all his horses and chariots, horsemen and soldiers, a very large host fully equipped for war. It included six hundred chariots, with men both on horses and in chariots, led by Pharaoh himself in a grand display of power and greatness. They were the most mighty men of Egypt, including its rulers and great men and the priests of its idol gods, gathered to make success more sure. It was a show of force meant to frighten and intimidate Israel.
They overtook Israel while encamped by the sea, at Pi-hahiroth at the Red Sea. Israel had been led into a valley with mountains around and the sea before them, with the sea in front and the army behind and no visible way of escape unless God intervened. Pharaoh with his counselors and people regretted letting Israel go, refusing to admit that the plagues and the slaying of the firstborn were God's judgment. They dismissed those judgments as natural events, and though they had suffered God's judgments upon Egypt they were hardened by continual rebellion.
They pursued to keep power over Israel and bring them back to Egypt by force into slavery, to regain their service. Their aim was also to frighten them, to redeem Egypt's glory and prestige, and to avoid derision from other nations for yielding to the power of the God of Israel. God himself chose and directed that encampment before the sea and told Moses just where to camp, because He knew Pharaoh would pursue. He foretold that He would be honored before Pharaoh and all his host, and the overtaking was appointed for the last display of His power, ending in the utter destruction of the Egyptian host as judgment against all the gods of Egypt.
Bringing Israel by the way of the sea instead of through the land of the Philistines showed Him compassionate as well as a God of judgment, for the Philistines would have treated them as fugitives from their masters and made war with them. At the overtaking the Egyptians shouted in triumph at finding Israel completely in their power. The Israelites' hearts failed them and they were greatly terrified.