As they wandered  the desert, the Israelites  carried the Tabernacle, and all its holy objects, so they could offer the sacrifices G-d had required of them. The Tabernacle provided a venue for these offerings, as the priests burned some or all of the sacrifices brought to them by the people. 

Fire was an essential component to the Israelites ritual sacrifices, and in this week’s Torah portion, Tzav, G-d commands the Israelite people to build a perpetual fire, never to be put out, under any circumstances.