This verse marks which member of the Elohim Family is the Creator God. He is Yahweh Elohim, the Lord God. The entry in Strong's for “Jehovah” (Yahweh) reads: “(the) self-Existent or Eternal: Jehovah, Jewish national name of God:—Jehovah, the Lord.” Zodhiates says of Yahweh, “The covenant name of God most prominently known in connection with His relationship with the nation of Israel.”
From the Bible, we see that Christ is the Creator God (John 1:1-3; Colossians 1:16) and that the Creator God is Yahweh—the God of the Old Testament. Therefore, it follows that Jesus Christ is the God of the Old Testament.
As further confirmation, notice two verses:
» “Thus says the LORD, the King of Israel, and his Redeemer, the LORD of hosts: 'I am the First and I am the Last.'” (Isaiah 44:6)
Yahweh of the Old Testament and Christ of the New refer to themselves as “the First and the Last” because both are the same self-existent, eternal Being.