There is yet another attribute of fire which is still more relevant to the knowledge of truth. As the fire’s flame rises upward it is visible only to an extent and then disappears into the vast space; it becomes invisible. The same is the case with the knowledge of truth; it is related with its knower only to a small extent and then it disappears into that which is unknowable. The visible part of reality is very tiny in comparison with its invisible part which is immense and infinite.
For all these reasons fire became a very useful and powerful symbol of knowledge. and Krishna ushered in jnan-yajna. Worship of knowledge is like worship of fire.
If you rightly understand the significance of fire as a symbol, you will know that worship of knowledge is eternal. While all other rituals that came into being with the discovery of fire have died because they were products of circumstances, the pursuit of knowledge remains with us forever. Knowledge is not bound with circumstances; it is eternal. So for the first time Krishna freed yajna from the fetters of time and events and yoked it to the eternal. From now on in the future, yajna or rituals will be in vogue in the way Krishna refashioned it; its meaning and purpose will be derived from Krishna alone. The pre-Krishna chapter of yajna is closed forever. It is now outdated and dead. If someone still talks of the yajna of the pre-Krishna days, he is only trying to perpetuate a dead and meaningless ritual. Now it is not possible to dance around fire in the old way, because fire is no more an event, it is an everyday affair.
Krishna talks about another kind of yajna which is japa-yajna or the ritual of chanting. The secret of japa is the same as that of knowledge. Japa at first burns all your thoughts, and then it burns itself – the thought of japa or chanting. And what remains is known as ajapa – wordless chanting. For this reason it is called yajna, because it works like fire.
Your mind is stuffed with thoughts, all kinds of junk. So you use a word for chanting, and with the help of this chanting you banish from your mind all other thoughts – except the one thought which is your word for chanting. However, when all other thoughts disappear, then this last thought – the thought of chanting – becomes unnecessary and it drops on its own. It is followed by a state of utter silence which is called ajapa or wordless chanting or non chanting. So ajapa too, is a kind of fire which first burns the fuel and then burns itself.
But there is a danger with chanting just as with knowledge. In fact, there is danger with every kind of spiritual discipline. There is no path from which one is not going to deviate. Every path leading to a destination has its by-paths of deviation, and you can use them to deviate from your journey. The truth is that we use paths more to digress from them than to reach.