3:1 Now Moses was shepherding the flock of his father-in-law Jethro, the priest of Midian, and he led the flock to the far side of the desert and came to the mountain of God, to Horeb. 3:2 The angel of the LORD appeared to him in a flame of fire from within a bush. He looked—and the bush was ablaze with fire, but it was not being consumed! 3:3 So Moses thought, “I will turn aside to see this amazing sight. Why does the bush not burn up?”

What are we to make of the ‘burning bush’?

Some think that this account is not to be taken literally.  According to Marc Zvi Brettler this story is ‘closer to figurative than reflective of some odd (or impossible) occurrence, such as the spontaneous combustion of a bush.’  He notes that in the Hebrew the usual word for ‘bush’ (si-ach) is not used, but rather sneh, which probably refers to the multicoloured Cassia obovata.  Brettler thinks that

‘this particular word was chosen for the story since the Hebrew word sneh is almost identical with sinai, as in Mount Sinai.  This is a classic case of prefiguration or hinting ahead, which is often used in the Bible.  In other words, this scene with the revelation of the divine name to Moses at the sneh/burning bush foreshadows the giving of the law to the Israelite community on Mount Sinai—which was also accompanied by a great fire that did not consume (see Exod 19:18).’

Although I would not wish to be dogmatic about the nature of the miracle (should we take it literally?  Was is perhaps an illusion caused by the setting sun behind a bush with reddish leaves?) I think that ‘explanations’ such as that by Brettler come too close to attempts to explain it away.

Stuart, while not appearing to suggest any mechanism for the phenomenon, supernatural or otherwise, also comments on the language used:

‘the similarity between the sounds of sĕneh, “bush,” and sı̂nāy, “Sinai,” fit his purposes. Indeed, so close are the two words that in Deut 33:16 the expression šōkĕnı̂ sĕneh, “the one who resided in the bush,” sometimes has been emended to šōkēn sı̂nāy, “the one who dwells on Sinai” (e.g., NRSV). At any rate, it is certainly conceivable that the mention of the bush, sĕneh, was designed also to become a reminder of its location, sı̂nāy.’

Others think that the phenomenon may be accounted for in a more mundane way.  But, as Alexander remarks:

‘From the details recorded, and given Moses’ experience of life in the wilderness, the burning bush cannot easily be accounted for by a natural phenomenon (e.g. the sun setting behind a red-leafed bush).’

According to Colin Humphries (The Miracles of Exodus), some desert bushes exude a flammable oil which, under some circumstances (such as being struck by lightning) can burn without destroying the bush itself.

As for the significance of the burning bush, we can suppose that it communicates the fact that God, while unspeakably holy, will not destroy his people, but will rescue them from their beondage.

Alexander comments that

‘The use of fire to represent the presence of God in accounts of theophanies may be due to its nonmaterial, formless, mysterious and luminous characteristics (Sarna 1991: 12).’

Alexander himself appears to favour an entirely supernatural explanation, but, apart from the comment just noted, he does not elaborate.

R.K. Harrison (ISBE) writes:

‘Louis Golding has described an analagous event which he witnessed in one of the wadis close to Mt. Sinai. Apparently the winds which were swirling down two or three confluent wadis met in cyclone form and sucked sand from the dry wadi bed as the column of air built up. This latter then moved across to a nearby acacia bush, and at that juncture was illumined by a burst of sunlight from behind a long bank of cloud. The effect was to make the whole hill appear to burst into flame. “The smoke of it soared in golden gusts. Every thorn was a spit of fire”; a situation which continued for several seconds until the cyclone finally passed along one of the wadis.’

Harrison does not commit himself to this explanation, and I wouldn’t do so, either.

Cole thinks that the question is unanswerable, and, in any case, unimportant:

‘What exactly did Moses see? Was it a supernatural vision (as in the case of some prophets, e.g. Ezek. 1) or was it an actual physical phenomenon? If the latter, did he see a bramble bush literally blazing in the desert; or the shrub called ‘burning bush’, in brilliant flower; or the sunset light falling full on a thorn bush and producing the effect of flames? All have been suggested in turn. It does not matter: whatever it was, God used Moses’ initial curiosity to attract him to the place. The true revelation, however, was not the burning thorn bush, but God’s word that came to Moses there.’