A Pillar of Fire was one of the manifestations of the presence of the God of Israel in the Torah

Torah

Torah- A scroll containing the first five books of the BibleThe Torah , is name given by Jews to the first five books of the bible—Genesis , Exodus , Leviticus , Numbers and Deuteronomy Torah- A scroll containing the first five books of the BibleThe Torah , is name given by Jews to the first five...

. According to Exodus, the pillar of fire provided light so that Jews

Jews

The Jews , also known as the Jewish people, are a nation and ethnoreligious group originating in the Israelites or Hebrews of the Ancient Near East. The Jewish ethnicity, nationality, and religion are strongly interrelated, as Judaism is the traditional faith of the Jewish nation...

 could travel by night during the Exodus

The Exodus

The Exodus is the story of the departure of the Israelites from ancient Egypt described in the Hebrew Bible.Narrowly defined, the term refers only to the departure from Egypt described in the Book of Exodus; more widely, it takes in the subsequent law-givings and wanderings in the wilderness...

 from Egypt

Egypt

Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

 (circa the 18th Dynasty

Eighteenth dynasty of Egypt

The eighteenth dynasty of ancient Egypt is perhaps the best known of all the dynasties of ancient Egypt...

; see dating of the Exodus). The pillar of fire is traditionally paired with the manifestation of the divine presence by day as the Pillar of Cloud

Pillar of Cloud (theophany)

A pillar of cloud was one of the manifestations of the presence of the God of Israel in the Torah. According to Exodus, the pillar of cloud guided Jews by day during the Exodus from Egypt . The pillar of cloud is traditionally paired with the manifestation of the divine presence by night as the...

. This was so they "could travel by day or night".

Usage

• Exodus 13:21-22. 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. Neither the pillar of cloud by day nor the pillar of fire by night left its place in front of the people.
• Exodus 14:24. During the last watch of the night the Lord looked down from the pillar of fire and cloud at the Egyptian army and threw it into confusion.
• Numbers
  Book of Numbers
  The Book of Numbers is the fourth book of the Hebrew Bible, and the fourth of five books of the Jewish Torah/Pentateuch....
  
   14:14. And they will tell the inhabitants of this land about it. They have already heard that you, O LORD, are with these people and that you, O Lord, have been seen face to face, that your cloud stays over them, and that you go before them in a pillar of cloud by day and a pillar of fire by night.
• Deuteronomy
  Deuteronomy
  The Book of Deuteronomy is the fifth book of the Hebrew Bible, and of the Jewish Torah/Pentateuch...
  
   1:33 Who went in the way before you, to search you out a place to pitch your tents in, in fire by night, to shew you by what way ye should go, and in a cloud by day.
• Nehemiah
  Nehemiah
  Nehemiah ]]," Standard Hebrew Nəḥemya, Tiberian Hebrew Nəḥemyāh) is the central figure of the Book of Nehemiah, which describes his work rebuilding Jerusalem and purifying the Jewish community. He was the son of Hachaliah, Nehemiah ]]," Standard Hebrew Nəḥemya, Tiberian Hebrew Nəḥemyāh) is the...
  
  9:12. By day you led them with a pillar of cloud, and by night with a pillar of fire to give them light on the way they were to take.
• Nehemiah 9:19. "Because of your great compassion you did not abandon them in the desert. By day the pillar of cloud did not cease to guide them on their path, nor the pillar of fire by night to shine on the way they were to take.