Question: "What did the pillar of cloud by day and the pillar of fire by night signify? (Exodus 13:21-22)"
Answer: The pillar of cloud by day and the pillar of fire by night guided the Israelites during their exodus from Egyptian bondage. This allowed them to travel by day and by night. Exodus 13:21–22 explains that God gave them the pillar of cloud by day to lead them in the way He wanted them to go and the pillar of fire by night to give light. The pillar was not just symbolism but a real phenomenon. We have no way of knowing how God made the pillar, but it was obviously a miraculous event that God used to lead them for their forty years in the wilderness. During the day the pillar guided their journey. During the night it gave light and, no doubt, comfort.
In addition to guidance for the Hebrews, the pillar was a testimony to other nations concerning God’s involvement with and protection of His people Israel. In Exodus 14:24 God troubled the Egyptians through the cloud, and Moses used this in Numbers 14:14 in his plea to God to not destroy the Hebrews because of their sin. God’s provision of the pillar was remembered in the prayer of the Jewish leaders in Nehemiah 9 as an instance of God’s care and provision for His people.
Exodus 13:22 says, “Neither the pillar of cloud by day nor the pillar of fire by night left its place in front of the people.” The pillar is a picture of God’s faithfulness and a lesson to us that God never leaves nor forsakes His people. He reminds us of this in Hebrews 13:5–6, “Let your conversation be without covetousness; and be content with such things as you have: for he has said, I will never leave you, nor forsake you. So that we may boldly say, The Lord is my helper, and I will not fear what man shall do to me.”