What did the pillar of cloud by day and the pillar of fire by night signify?

This is from Exodus. God helped the Israelites travel by night and day by providing light. (

Exodus 13:21-22)

ANOTHER ANSWER:

The entire "exodus" from Egyptian slavery [symbolic of man's bondage to sin - disobedience to God's Commandments - I John 3:4] orchestrated by God is an encapsulation of the Salvation process.

A person's trust in the shed blood of the lamb [Christ's blood] struck on the doors and Windows of their homes; the access points to their homes where they live, blots out all past sins [liberates him from the penalty of sin; death: set free from Egypt]. From that point in one's life, they live in newness of life... they are to RUN AWAY FROM SIN [Egypt] until the time of the Salvation of the LORD.

Until that time, the Power of the LORD [the column of the cloud by day and the pillar of fire by night], meanwhile, stands between them and Satan and his demons [Pharaoh and his armies] throughout the remainder of their life, preventing the Devil's dragging them back into sin [Egypt] and bondage to it.

It's a struggle to overcome throughout one's life... but trusting in that awesome protective cloud and fire... though one feels like their backs are against a wall [the Red Sea]... will result in their ultimate "delivery" [re-birth] into the Immortal Family of God:

"And Moses said unto the people, "FEAR YE NOT, stand still, and SEE THE SALVATION OF THE LORD, which He will shew you to day: for the Egyptians [Satan and his demons] whom ye have seen to day, ye shall see them again no more for ever. The LORD SHALL FIGHT FOR YOU, and ye shall hold your peace." (Ex.14:13-14 KJV)

The entire process of the LORD's Salvation is condensed in the Exodus account. And the LORD's [Christ's] protection from the Devil is pictured in the column of the cloud and pillar of fire:

"I don't want you to forget, dear brothers and sisters, what happened to our ancestors in the wilderness long ago. God guided all of them by sending a cloud that moved along ahead of them, and He brought them all safely through the waters of the sea on dry ground. As followers of Moses, they were all baptized in the cloud and the sea. And all of them ate miraculous food [the bread...Word of God... from heaven - John 6:32-35], and all of them drank the same miraculous water. For they all drank from the miraculous ROCK THAT TRAVELED WITH THEM, and THAT ROCK WAS CHRIST." (I Cor.10:1-4 NLT New Living Translation)