Exodus 13:21-22 New International Version (NIV)
21 By day the Lord went ahead of them in a pillar of cloud to guide them on their way and by night in a pillar of fire to give them light, so that they could travel by day or night. 22 Neither the pillar of cloud by day nor the pillar of fire by night left its place in front of the people.
God gave the Hebrews a pillar of cloud by day and a pillar of fire by night so they would know day and night that God was with them on their journey to the Promised Land. God appeared to the Hebrews in these physical forms to light their path, protect them, provide reassurance, and inspire them. What has God given you so that you can have assurance? He has given you the Bible. He has given you the Holy Spirit to help you and guide you. Look to God’s Word for reassurance of his presence. The Hebrews had the pillar of cloud by day and the pillar of fire by night. You have God’s Word day and night. He is with you and helps you on your journey.