The Symbolism of Yajna

Ghee, the oil that's extracted from butter, was considered extremely valuable. So you are offering something of great value to Ishura through this fire. Many people wrongly think that Yajna is worship of Agni, Agni meaning the God of fire. You could be worshiping Shiva by means of that fire, or Indra by Means of That Fire and not necessarily Agni. The flames carry that offering upwards symbolically, conveying your offering to the gods.