30. i. That the Lord from eternity is Jehovah, is known from the Word; for the Lord said to the Jews,
Verily I say unto you, before Abraham was, I am (John 8:58).
And He says in another place,
Glorify Thou Me, O Father, with the glory which I had with Thee before the world was (John 17:5).
By this is meant the Lord from eternity, and not a Son from eternity; for "the Son" is His Human that was conceived of Jehovah the Father, and born of the virgin Mary, in time, as has been shown above.  That the Lord from eternity is Jehovah Himself, is evident from many passages in the Word, of which at present there shall be adduced only these few:
It shall be said in that day, THIS IS OUR GOD; we have waited for Him that He may deliver us; THIS IS JEHOVAH, we have waited for Him; we will rejoice and be glad in His salvation (Isa. 25:9).
From these words it is evident that Jehovah God Himself was awaited.
The voice of one crying in the wilderness, Prepare ye the way of JEHOVAH, make plain in the solitude a path for OUR GOD. The glory of JEHOVAH shall be revealed, and all flesh shall see it together. Beheld, THE LORD JEHOVAH shall come in strength (Isa. 40:3, 5, 10; Matt. 3:3; Mark 1:3; Luke 3:4).
Here, too, the Lord is called Jehovah, who should come. 
I Jehovah will give thee for a covenant to the people, for a light of the nations. I Jehovah, this is My name and My glory will I not give to another (Isa. 42:6-8).
"A covenant to the people," and "a light of the nations," is the Lord as to the Human; and as this is from Jehovah, and has become one with Jehovah, it is said, I Jehovah, this is My name, and My glory will I give to another, that is, not to another than Himself. To give glory, means to glorify, or to unite to Himself. 
THE LORD whom ye seek, shall suddenly come to His temple (Mal. 3:1).
By the "temple" is meant the temple of His body (John 2:19, 21).
THE DAY-SPRING FROM ON HIGH hath visited us (Luke 1:78).
"The day-spring from on high" also is Jehovah, or the Lord from eternity.
From what has been said it is evident that by the Lord from eternity is meant His Divine a Quo,* which in the Word is "Jehovah." But from the passages to be quoted below, it will be evident that by Lord, and also by Jehovah, after His Human was glorified, is meant the Divine and the Human together, as a one; and that by the Son, alone, is meant the Divine Human.
* Literally, the divine from which; that is, the Divine which is the source. [Tr.]