ABC:Exodus 6

Verse 2
Don Morgan's list at Infidels claims this is a contradiction and makes the following comments (italicized).

God was already known as "the Lord" (Jahveh or Jehovah) much earlier than the time of Moses.

Genesis 2:4 These are the generations of the heavens and of the earth when they were created, in the day that the LORD God made the earth and the heavens,

Genesis 4:26 And to Seth, to him also there was born a son; and he called his name Enos: then began men to call upon the name of the LORD.

Genesis 12:8 And he removed from thence unto a mountain on the east of Bethel, and pitched his tent, having Bethel on the west, and Hai on the east: and there he builded an altar unto the LORD, and called upon the name of the LORD.

Genesis 22:14 And Abraham called the name of that place Jehovahjireh: as it is said to this day, In the mount of the LORD it shall be seen. 15 ¶ And the angel of the LORD called unto Abraham out of heaven the second time, 16 And said, By myself have I sworn, saith the LORD, for because thou hast done this thing, and hast not withheld thy son, thine only son:

Genesis 26:25 And he builded an altar there, and called upon the name of the LORD, and pitched his tent there: and there Isaac's servants digged a well.

God was first known as "the Lord" (Jahveh or Jehovah) at the time of the Egyptian Bondage, during the life of Moses.

Exodus 6:2 And God spake unto Moses, and said unto him, I am the LORD: 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.

The Scofield Study Bible III makes some excellent points on this passage:

(1) The statement, 'by my name JEHOVAH was I not known to them' can also be translated as a rhetorical question, 'By my name JEHOVAH was I not known to them?' (2) In the O.T. the verb 'to know' generally means far more than to have an intellectual knowledge. There are many instances of this, such as Amos 3:2: 'You only have I known of all the families of the earth.' (3) The patriarchs were familiar with the name Jehovah, but their experience of God was largely that of Him as El-Shaddai (compare Gen. 17:1, note), the One who provided for all their needs. Here in Ex. 6:3 God tells Moses that He is now about to be revealed in that aspect of His character signified by Jehovah - that is, His covenant-relation to Israel as the One who redeems her from sin and delivers her from Egypt (compare vv. 6-8). (4) Actually there is no contrast in Ex. 6:3 between Elohim and Jehovah, the names in this text being El-Shaddai and Jehovah.

-The Scofield Study Bible III, Oxford University Press

As pointed out by the Scofield, the key passage Exodus 6:3 can be translated from the original Hebrew as a rhetorical question, thus removing all claims of a contradiction here. Henry M. Morris of ICR concurs with this explanation: "The easiest resolution of the apparent contradiction is to regard the last clause as a rhetorical question (quite permissible in the Hebrew)– 'by my name JEHOVAH was I not (also) known to them?'" The second possibility mentioned, that the expression "know Jehovah" referred to more than a simple awareness of His existence but rather an experiential relationship is argued by Apologetics Press apologist Eric Lyons.