When Abram was ninety-nine years old, the Lord appeared to him and said, “I am God Almighty; walk before me faithfully and be blameless.
Genesis 17:1 (NIV)
Prior to Genesis 17, God has been identified by His Name, which speaks to perpetual presence: I AM. ALWAYS.
But when God seals his covenant with Abram in Genesis 17, the earth must have shaken.
I am EL SHADDAI. I am GOD ALMIGHTY!
And Abram threw himself on his face.
The rabbis say the most profound thing about these two names of God.
The correct interpretation of the divine names is as follows: Shaddai is an adjective describing God’s power over creation. The Tetragrammaton, God’s revered and awesome name, stands in contrast to it. The world exists by virtue of these two names.
Ibn Ezra on Genesis 17:1:1