Hello there my friend!
Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God;
Romans 3:25
And almost all things are by the law purged with blood; and without shedding of blood is no remission.Hebrews 9:22
Remissions of sins that is.
When i stare upon the bloody and bleeding body of Jesus, I see a God who saw this world and Had compassion and mercy and Grace all in one, and took His grace and had it become man.
You are correct! He is IAM THAT I AM, Jesus bridges the gap between God and man, Old Testament saints were communicated with God through the spirit of God the Holy Spirit of God which revealed truths and things to come through prophets that spoke as spokesmen for God.
Now God to reconcile the world unto Himself through what Was to be a man and that man was Jesus, You might ask why God have to do this, He is All-Powerful!
Correct!, but why did God ask for sacrifices in the Old Testament if He was all powerful? Think about it.
The Methods of God and His Spiritual understanding surpasses that of man and causes man to question God.
It is written:For my thoughts are not your thoughts, neither are your ways my ways, saith the LORD. For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts. For as the rain cometh down, and the snow from heaven, and returneth not thither, but watereth the earth, and maketh it bring forth and bud, that it may give seed to the sower, and bread to the eater: So shall my word be that goeth forth out of my mouth: it shall not return unto me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it.
Isaiah 55:8-11
When you see a piece of bread for the first time, you don't have a clue to as how it was made nor where it came from, but as within these verses the same Holds True with God. Bread comes from wheat which is planted by SEEDS, Understand my friend?
God loved the world so much that He became a humble and obedient servant to fulfill the Ultimate Will of God since the beginning of eternity.
Why? Just as certain commandments where given by God concerning this verse:and the whole assembly of the congregation of Israel shall kill it{Lamb} in the evening. And they shall take of the blood, and strike it on the two side posts and on the upper door post of the houses, wherein they shall eat it. And they shall eat the flesh in that night, roast with fire, and unleavened bread; and with bitter herbs they shall eat it. Exodus 12:7-9
Makes sense to you as to why this must be done?
God Bless!