STAGE ONE
“I will make of you a great nation, …”
The fulfillment of these words cover the period of time from the days of Yitzchak until the Exodus from Egypt.
Avraham was commanded to leave his place of security. Where all other nations develop out of their place of birth and are attached to their homeland, Avraham is to begin building his nation without a birthplace or land.
All the external conditions and natural circumstances will be against the formation of this nation, so it will be plain for all to see that God Himself is the Creator of Israel. (among the many indicators will be that Avraham and Sara were old and childless and Sara conceived miraculously.)
All other nations have their shared lands to form their common bond. In the case of Avraham it is his spirit that will be the uniting element that forms the nation. That is the meaning of the expression referring to God as The God of Avraham – אלקי אברהם. The spirit of Avraham’s relationship with God and faith in God will be the base of the formation of this nation.
(Of course, God is the God of the whole universe as Malki Tzedek later says that God is the Master of all Heaven and Earth – קונה שמים וארץ (14:19). However the emphasis here on Avraham is about how Avraham perceived God and began to set the world straight on the correct understanding of God.)
Beraishis 12:2
pages 290-291