A name expresses more than mere identification. God's name expresses His nature and operations, so He must explain His name to Moses. The Israelites in Egypt did not know God. They undoubtedly had a memory of Him, or they would not have cried out to Him to relieve them of their bondage. However, they had no relationship with Him and therefore did not really know Him. They knew of Him, but they did not know Him.
By comparison, neither did we know Him when we were in spiritual Egypt, even though we were not completely ignorant of Him. When Paul spoke to the pagan Greeks in Acts 17, he spoke assuming that they knew somewhat of the God he represented. He introduced his God to them as the "unknown God," and explained enough about Him to enable them to relate to Him. Nor were they completely ignorant of the God of creation. Nevertheless, when in spiritual Egypt, ignorance of God and His true nature and operations is pretty deep, and that is part of humanity's basic problem.
John W. Ritenbaugh
A Pre-Passover Look
Other Forerunner Commentary entries containing Exodus 3:13: