When the sun had set and darkness had fallen, a smoking firepot with a blazing torch appeared and passed between the pieces. On that day the Lord made a covenant with Abram and said, “To your descendants I give this land, from the Wadi of Egypt to the great river, the Euphrates— the land of the Kenites, Kenizzites, Kadmonites, Hittites, Perizzites, Rephaites, Amorites, Canaanites, Girgashites and Jebusites.” – Genesis 15:17-21

Though the symbolism of the “smoking firepot” can be linked to the darkness and smoke that Moses encountered on Mount Sinai (Exo 19:18), it is more likely that it along with the “blazing torch” are revisited in the pillar of cloud and fire (Exo 13:21). This reflection is incredibly crucial for it is here that God’s covenant with Abram is being cut. The Lord is making His promise to Abram and to Abram’s seed and when the Lord comes down and renews this covenant He again takes on the symbolic forms of the covenant (Exo 13:17-22; 14:19-24; 33:9-10; etc.).
It is worth noticing in conclusion that this is in fact the symbolism of Jesus Christ as He conquers the world (Rev 10:1).