PILLAR OF CLOUD TO LEAD BY DAY; PILLAR OF FIRE TO LEAD BY NIGHT. 

And the Lord went before them by day in a pillar of cloud to lead the way, and by night in a pillar of fire to give them light, so as to go by day and night. He did not take away the pillar of cloud by day or the pillar of fire by night from before the people.
Exodus 13:21-22
However, when He, the Spirit of truth, has come, HE WILL GUIDE YOU INTO ALL TRUTH; for He will not speak on His own authority, but whatever He hears He will speak; and He will tell you things to come. John 16:13