Matthew Poole and continuators on Exodus 6:3

3 And I appeared unto Abraham, unto Isaac, and unto Jacob, by the Name of God Almighty, but by my Name JEHOVAH was I not known to them .

Quest. How is this true, when God was known to them and called by the name Iehovah, Gen. 15. 7. and 26. 24. &c. Ans. 1. He speaks not of the letters or syllables, but of the thing signified by that name. For that denotes all his perfections, and, amongst others, the eternity, constancy and immutability of his nature and will, and the infallible certainty of his word and promises. And this, saith he, though it was believed by Abraham, Isaac, and Iacob, yet it was not experimentally known to them: for they onely saw the promises afar off, Heb. 11. 13. Ans. 2. This negative expression may be understood comparatively, as many others are, as Gen. 32. 29. Mat. 9. 13. 1 Cor. 1. 17. q. d. They knew this but darkly and imperfectly, which will now be made known more clearly and fully.

Marginal references: Gen. 17. 1. and 48. 3.; chap. 3. 14.