To Abraham, Isaac and Jacob I appeared as El Shaddai, but I did not make my name Yahweh known to them (Exod 6:3, NJB).
Exod 6:3 is a notorious crux. On the conventional translation, it generates a formal contradiction. In Genesis, the narrator repeatedly designates God as Yahweh. Moreover, characters in Genesis, including patriarchs, refer to God as Yahweh. So how do we resolve this formal contradiction? Various harmonizations have been proposed:
1. On the liberal view, this is evidence of divergent traditions. The final redactor of the Pentateuch failed to synthesize these traditions.
But even if we deny the inspiration or historicity of the Bible, that's a highly implausible explanation. This isn't an incidental reference, but occurs at a conspicuous and strategic point in the narrative. It would be incredibly clumsy for the alleged redactor to preserve such a glaring contradiction.
2. Some scholars (e.g. Driver, Garrett, Hamilton, Martin, Stuart), challenge the conventional translation. They render the second clause as an interrogative rather than an indicative: "And by my name Yahweh, did I not make myself known to them?"
In his commentary, Duane Garrett presents the most sophisticated argument for that rendering. He regards the passage as a poetic strophe. He discusses the parallelism. He denies that the preposition means "by my name" rather than "and my name."
He stresses that Exod 6 is about continuity, not novelty. The same God who made a covenant with Abraham, who spoke to the patriarchs, and guided them, has returned to fulfill his promises. Sarna makes a similar point.
But while that explanation merits a respectful hearing, I'm unconvinced:
i) A basic problem with rendering the second clause as a rhetorical question is that we still have an implied contrast between God appearing to the patriarchs as El Shaddai and his identity as Yahweh. If the second clause is a rhetorical question, what's the function of El Shaddai in this passage?
ii) That's reinforced by v7:
I shall take you as my people and I shall be your God. And you will know that I am Yahweh your God, who have freed you from the forced labour of the Egyptians (Exod 6:7, NJB).
Once again, knowing God as Yahweh seems to serve as a foil, in implied contrast to past experience.
iii) We should resist a false dichotomy between continuity and discontinuity. It can be the same in one respect, but different in another. The same in terms of who God is, but different in terms of what he does. The God of the Exodus is the same God as the God of the patriarchs. There you have continuity–indeed, identity. Yet this may be something new in terms of what he is now doing.
3. A third explanation harmonizes the formal contradiction by supposing the use of Yahweh in Genesis is anachronistic. It reflects the viewpoint of the narrator rather than the viewpoint of the characters. The retrospective timeframe of the narrator rather than the timeframe of the people he quotes.
In general, I think that explanation is unobjectionable. When writing about the past, we sometimes update usage for ease of reference. If, say, we describe the migration of Indians to the New World, we write about how they (allegedly) crossed the Bering land bridge during the last ice age, then came down through Canada. Some of them settled in the Mississippi river valley. Some settled in New Mexico. Some settled in Mexico. And so on.
Of course, those place-names didn't exist at the time of the migration. We're using modern designations for the distant past.
Likewise, the NT records Jesus referring to God as theos and kurios. But Jesus usually spoke in Aramaic. So that's a Greek translation of what Jesus said.
By the same token, did Abraham speak Classical Hebrew? Presumably, his mother tongue was Akkadian. When Genesis quotes Abraham, or conversations between Abraham and God, that's probably a Hebrew translation.
Going back even further, Eve is quoting referring to God as Yahweh (Gen 4:1). But did Eve speak Classical Hebrew?
Yet while I think that explanation is has considerable merit in its own right, I don't think that's sufficient to harmonize Exod 6:3 with Genesis. For one thing, it's too subtle to expect the average reader or listener to draw that distinction.
If, moreover, the narrator uses Yahweh in Genesis in part to stress the continuity of the divine referent, it would be really jarring to record a statement in Exod 6:3 that seems to dramatically contradicts that usage. So while I think the appeal to anachronistic usage is probably correct on its own terms, that's not enough to resolve the tension.
4. I think (3) needs to be complemented by an additional consideration. As scholars like Waltke point out, "to know" in Hebrew can have connotations over and above propositional knowledge. Rather, it can be a synonym for "experience". Not just knowledge by description, but knowledge by acquaintance.
The distinction, then, is that the patriarchs didn't know God as the God of the Exodus. They didn't live to witness God returning to carry out his promises by miraculously delivering the seed of Abraham from Egyptian bondage. They didn't experience God's covenantal fidelity in that respect.
5. And here I think it maybe useful to make an additional observation. In paganism, there's no presumption that gods are immortal. Gods come into existence. Gods can be killed by other gods.
The notion of a God who always existed, a God who always will exist, is fairly alien to paganism. That's a result of revelation.
In that respect, the fact that Yahweh was still around centuries later to keep his promise is more impressive than how he provided for the patriarchs during their lifetime. It's easy for modern readers to lose sight of that, because we take the eternity of God for granted. There was never a time when God did not exist. There will never be a time when God does not exist. But the fact that Yahweh came back would, in itself, be impressive to ancient readers.
Not only were heathen gods limited in time, but limited in space. They had geographically restricted jurisdictions. But Yahweh invades Egypt. He beats the gods of Egypt on their own turf.