Answer: Yes, there is. Isaiah 48:16. The context of this passage begins in 48:12 where it is God doing the speaking. He is seen as the God in control, He is the God of eternity, creation, human affairs, prophecy and the God of the Trinity.
16a Come ye near unto me, hear ye this; from the beginning I have not spoken in secret; from the time that it was, there am I. Then in verse 16b He clearly shows that He is the God of the Trinity; and now the Lord Jehovah has sent me, and his Spirit. The context of this statement began in verse 12, and throughout the entire passage, One Person and One alone has been speaking. Now, in verse 16b, there are three Persons. The first Person is the Lord Jehovah. He is God the Father. The second Person is the Spirit, He is God the Holy Spirit. The third Person is seen in the personal pronouns “I” (v. 16a) and “me” (v. 16b). He is the One who has been speaking since verse 12. He is the One who has declared Himself to be the God of eternity, the God of creation, the God of human affairs, and the God of prophecy. Hence, this “I” has to be a deity. He is God the Son.
With this verse, the Second Person of the Trinity is introduced, and the main topic of the next section (chapters 49–57) will be Messiah the Servant, the One who has been speaking all along.
The second clearest passage concerning the Trinity will also be in Isaiah (Isa. 63:7-14).
Arnold G Fruchtenbaum, Ariel's Bible Commentary: The Book of Isaiah (San Antonio, TX: Ariel Ministries, 2021), pp. 515-517
