Hebrews 4:8-9- "Though he were a Son, yet he (Jesus) learned obedience by the things which he suffered (went through); And being made perfect, he became the author (source) of eternal salvation (life) unto all them that (would choose to) obey him."
And God in the OT changed His mind (as He did many times in the OT) after Moses had a talk with Him, and did not do the evil or calamity that He swore to do with certain people, and had to grow and/or learn/develop along the way as well, etc...
Exodus 32:11-14- "And Moses besought the LORD his God, and said, LORD, why doth thy wrath wax hot against thy people, which thou hast brought forth out of the land of Egypt with great power, and with a mighty hand? Wherefore should the Egyptians speak, and say, For mischief did he bring them out, to slay them in the mountains, and to consume them from the face of the earth? Turn from thy fierce wrath, and repent of this evil against thy people. Remember Abraham, Isaac, and Israel, thy servants, to whom thou swarest by thine own self, and saidst unto them, I will multiply your seed as the stars of heaven, and all this land that I have spoken of will I give unto your seed, and they shall inherit it for ever. And the LORD repented of the evil which he thought to do unto his people. (and did not do it, etc) (but was going to, etc)...
God in the OT also went through a whole slew of more human like behavior and emotions that just is not at all even possible for a God who always knew/knows all from the very, very beginning, etc... He was also at times shocked, or taken aback, and "hurt", etc, which is also just not not possible for a God who always knew/knows all from the very, very beginning, etc...
But I guess I don't expect you to understand "logic" though...
Either way, the purpose for the other two was to show us God the Father who could not show Himself to us otherwise, because that is/was the one thing His full omniscience from the very beginning, or from before even making anything, or creating anything or anyone, etc, just prevents absolutely, etc...
But I guess I don't expect you to understand that "logic" either, etc...
Where the two meet or are reconciled (Jesus Christ, or the God-Man, and God in the OT, or God the Spirit) where their two ways are fully reconciled/rejoined, there, in that middle, is where we will see God the Father, etc...
And we will also understand what that One (God the Father) might have been like if He were in time with us also, etc...
Which is just not at all even possible for Him to ever do without the other two, etc...
Who also just could not be made fully omniscient from the very beginning (those other two), or none of this would have been/would be even possible, etc...
They are pretty much omnipotent in this world though, the other two are/always were, etc, and God the Spirit, or God in the OT, who either became or always was, etc, the Holy Spirit and the Spirit of Christ in the NT, etc, is omnipresent inside the heart/being/soul/spirit of every new born again person or true believer, etc...
Satan is on the outside, etc, but that's another topic/story, etc...
And they are/always were "partially omniscient" also, (the other two, etc), as we see some of that in scripture, etc, just not all the way until maybe later on maybe, etc... "Maybe", etc...
That part is still up for debate, etc...
But not the rest of it, etc...
God Bless!