When Pharaoh let the people go, God did not lead them by way of the land of the Philistines, although that was near. For God said, "Lest the people change their minds when they see war and return to Egypt." But God led the people around by the way of the wilderness toward the Red Sea. And the people of Israel went up out of the land of Egypt equipped for battle. Moses took the bones of Joseph with him, for Joseph had made the sons of Israel solemnly swear, saying, "God will surely visit you, and you shall carry up my bones with you from here."
Exodus 13:17-19
These verses are full of interest. We are told that God did not lead the people by the shortest and most direct route, through Philistia, but by a more devious and roundabout one, through the wilderness of the Red Sea. The reason given for this is that the people might have lost heart when they saw the prospect of war. The fact is, a suppressed and subjugated people do not turn overnight into a trained army, and Israel would almost certainly lack moral and physical vigour after long years of slavery. It is true that God could have given them miraculous power to defeat the Philistines, but there is an economy of miracle with God, and He did not. Rather, He trained Israel in the wilderness to be soldiers. And there is ample evidence in the rest of Exodus both that they needed much training and that they received it in the hands of a wise and patient God. The reference to the bones of Joseph in 19 (cf Hebrews 11:22) is strangely moving, and bears witness to the idea of continuity in the plan and purpose of God, reminding us that the story in which Joseph was once the chief actor is the same story in which Moses has now taken the central place. Joseph had discerned by faith that Israel's sojourn in Egypt was to be only a temporary one, and such was his confidence in the purposes of God that he was able to give commandment that his bones should be brought up to the Promised Land with Israel on their return. And Moses, with the same lively sense of the continuity of the divine purpose, fulfils the patriarch's command. What bedrock faith in God these men had!