"God is Fire": Trying to Source an Analogy for Prayer

Question

I remember reading once a very clever analogy, which I was sure that I had found in the writings of Yeshayahu Leibowitz (who sourced it, from memory, in the writings of the Rav, R' Yosef Ber Soloveitchik, who himself sourced it in the Rambam), but I can no longer locate it at all. In essence, the analogy stated that God is like fire. Different objects, when dropped into the fire, react differently. Some become hard. Some become soft. Some let off smoke. Some change their hue. Some make a noise. Some might explode. But while all of these different reactions can be found, at no stage is the fire anything other than a fire; the difference in responses to it is to be found in the different objects that come into contact with it.

So too, the analogy concluded, when it comes to our relationship with God. When we pray, we change ourselves in order that God might interact more favourably with us. We do not hope for God to change in any way, but for ourselves to change instead. God's influence upon the world is constant and unchanging; it is we who are in flux.

Does this analogy sound familiar to anybody? If you can direct me to a printed source (be it in the writings of the Rav, or Prof. Leibowitz, or whomever it was who came up with this), I would be much obliged.

Answer 1

From zaq's answer to a related question:

In the Moreh Nevuchim [(Part 1 ch.53)], Rambam explains how God's attributes should be understood without compromising God's unchangingness.

He compares God's mood to a fire. If you put ice in a fire, it melts, then evaporates. If you put clay in a fire, it hardens. If you put wood in a fire it burns... The fire causes many different and contrasting effects without changing the fire's properties. The same "fire melts certain things and makes others hard, it boils and burns, it bleaches and blackens." It is the properties of each individual material that elicit a different interactions with fire.

Answer 2

Rav Saadia Gaon discuses Deuteronomy 4:24 to illustrate an instance where Scripture is not interpreted according to its "literal" meaning,

"Likewise we find for the statement of Scripture: For the Lord thy God is a fire, a good interpretation, by way of metaphor or analogy, to the effect that God's punishment is like a consuming fire that burns up quickly, as Scripture says elsewhere: For a fire is kindled in my nostril (Deut. 32:22). (The Book of Beliefs and Opinions 7:2, Yale/Rosenblatt page 415-416)

The Rambam cites Deuteronomy 4:24 in Yesodei haTorah 2:4

What is meant by the prophets' statements that they saw an angel of fire or with wings? All these are prophetic visions and parables, as [Deuteronomy 4:24] states: "God, your Lord, is consuming fire," though He is not fire and [the description of Him in this manner] is only metaphoric. Similarly, [Psalms 104:4] states: "He makes His angels as winds...."

and again in the Guide to illustrate alternative usages of the verb to eat

"(God) is a destroying (lit. eating) fire" (Deut. iv. 24), that is, He destroys those who rebel against Him, as the fire destroys everything that comes within its reach. Instances of this kind are very frequent." (Guide for the Perplexed 1:30)

I have yet to see anywhere which breaks down the analogy in the manner you have described and it is possible that this is what is added to by the latter sources who cite the Rambam (or others) in support of the general approach to the verse.