What person(s) of the Trinity were the people of the Old Testament interacting with?

The God of the Old Testament is Yaweh (The Father).The christians of the Old Testament had no idea of the Trinity. There was no physical incarnation (Jesus) as we have in the New Testament.In as much as the Son and the Holy Spirit were there in the beginning, people of the time were not aware of their existence. Does the Father still want that interaction with us - the New Testament church? My answer would be, "Yes". The Son was sent to draw us back to the Father and upon His death on the cross, the way was once again opened for us to do just that.The modern day church seems to have an affiliation to the One that was sent rather than with the One that sent Him.

The old testament people had been interacting with all the three persons of the God Head.

God The Father of the nation of Israel / Individuals Deut 32:6, Isa 63:16, Jeremiah 3:4, Jeremiah 3:19 , Mal 1:6, 2 Sam 7:14 ,1 Chron 17:13 Psalm 68:5

The Angel of the Lord - Christophany Exodus 3:2-6, Genesis 16:7, Judges 2:1-2, Judges 13:16-22, Zechariah 3:1-2, Zechariah 1:12-13, Psalms 34:7

Holy Spirit Genesis 1:2, Job 33:4, Psalm 104:30,Nehemiah 9:20,Job 32:8, Psalm 51:11,Psalm 139:7,Exodus 31:3

One old testament verse that supports Trinity is Isa. 48:16-17 "Come near to Me, hear this: I have not spoken in secret from the beginning; from the time that it was, I was there. And now the Lord GOD and His Spirit have sent Me."Thus says the LORD, your Redeemer, the Holy One of Israel: "I am the LORD your God, who teaches you to profit, who leads you by the way you should go.

Lets examine this again because this theme occurs over and over Isaiah 48:16:“From the beginning from the time that it was, I was there: (1st person) and now the Lord GOD (2nd person) and His Spirit, (3rd person) hath sent me (1st person).”

The Trinity Is Foreshadowed In Benedictions

The Trinity is also foreshadowed in the triple benediction of Numbers 6:24-27. The LORD bless you and keep you; the LORD make his face shine upon you and be gracious to you; the LORD turn his face toward you and give you peace. So they will put my name on the Israelites, and I will bless them.

The doxology of Isaiah 6:3 also gives hint of the Trinity. And they were calling to one another: Holy, holy, holy is the LORD Almighty; the whole earth is full of his glory (Isaiah 6:3).

It's usually unwise to try to separate out the persons of the Trinity from one another, unless two of them are clearly interacting. The nature of the Trinity means that if you are interacting with one, for most purposes you may as well be interacting with all.

When Jesus talks of "The Father" it's certainly clear to those listening to him that he means "God"; i.e. YHWH. Jesus also identifies himself with YHWH, yet the scriptures also draw a distinction between Jesus and the Father - it is part of these complexities that led to the doctrine of the Trinity. It is clear from other parts of scripture that God is not divided into three - the whole of God exists in three persons.

The Old Testament also clearly speaks of occasions when the Spirit of God interacted with people, by which we have to understand the Holy Spirit.

In short, the simplest way to approach this is to assume that all interactions in the Old Testament were with God as a whole - unless the Spirit is clearly named. Attempting to make any finer distinction is fairly meaningless, and to insist that the interaction be with only one is to misunderstand the nature of the Trinity.

John 6:46 οὐχ ὅτι τὸν πατέρα τις ἑώρακέν εἰ μὴ ὁ ὢν παρὰ τοῦ θεοῦ οὗτος ἑώρακεν τὸν πατέρα

Not that anyone has seen the Father except he who is from God; this [one] has seen the Father.

Nobody has ever seen the Father.

If they saw God in the Tanakh (and, they did), then it was not the Father.

Conundrum?

No. I can quote many Early Church Fathers who insist that they saw pre-incarnate Christ. But, hey, let's dig a little deeper, shall we?

John 12:41 Isaiah said these things when he saw his glory and spoke about him.

Isaiah 6:1 In the year that king Uzziah died, I also saw Adonai sitting upon a throne, high and lifted up, and his train filled the temple.

So, they saw the pre-incarnate Son of God. If you read the targumim (Aramaic translation/ interpretation of the Hebrew Tanakh), you will see that in many places where it says that YHVH is interacting with His creation, the targumim say that it is the Meimra d'YHVH (Word of YHVH) interacting with the creation.

Quite phenomenal if you ask me. =)