Lech Lecho - 12

Lech Lecho 12:1
וַיֹּאמֶר יְהוָה אֶל-אַבְרָם, לֶךְ-לְךָ מֵאַרְצְךָ וּמִמּוֹלַדְתְּךָ וּמִבֵּית אָבִיךָ, אֶל-הָאָרֶץ, אֲשֶׁר אַרְאֶךָּ.
And Hashem said to Avraham, go for yourself from your land, from your birthplace and from the house of your father, to the land which I will show you
Avraham Avinu expended great effort in deep thought to arrive at a clear understanding of the manner in which God directs the world. He could not achieve a full understanding because the land in which he lived, Ur Kasdim, was outside of the land of Israel where the impure air prevented him from achieving full understanding. God led him to the land of Canaan where the air provides wisdom and nothing would prevent him from reaching the highest degree of understanding. 
This is the meaning of אל הארץ אשר אראך, to the land where I will show you all that you wish to see, which cannot be seen elsewhere. This is also why we are taught that לך לך means to go for your own benefit, it was for Avrahams benefit as he would finally receive what he was seeking. 
אשר אראך can also be understood to mean "the place where I will show myself to you," as well as to any others who would come to seek Him.

Lech Lecho 12:2
וְאֶֽעֶשְׂךָ֙ לְג֣וֹי גָּד֔וֹל וַאֲבָ֣רֶכְךָ֔ וַאֲגַדְּלָ֖ה שְׁמֶ֑ךָ וֶהְיֵ֖ה בְּרָכָֽה:  And I will make you into a great nation, and I will bless you and make your name great and you shall be a blessing

(In the hierarchy of Sefiros the third one is Bina which denotes taking an idea and breaking it down into its constituent parts in order to be able to take the idea from the theoretical to the practical. In the four letter name of God the first letter ה symbolizes Bina. CL)

There in the land of Israel God will bring him to the level where the roots of his soul will thrive. There he will receive the blessing of Bina, the blessing that rests directly above Chesed (which is the unique trait of Avraham. CL) Bina, symbolized by the letter ה will be tied to the name of אברם (Avram), making the size of his name greater as it goes from four letters to five. אברם becomes אברהם. At that point all of the spiritual power of Bina will diffuse through the 248 limbs of his body (Avraham has the Gematria (numerical value) of 248.) 

Perhaps Avraham will be concerned that he only carries one letter of God's name in his own name and therefore he will not be able to fully share the spirituality of God with others, therefore וֶהְיֵ֖ה , and you will be, a word which consists of all the letters of God's name (albeit rearranged) a blessing. Once he is connected to one part of the name, he is connected to the whole name.

Lech Lecho 12:10

וַיְהִי רָעָב בָּאָרֶץ וַיֵּרֶד אַבְרָם מִצְרַיְמָה לָגוּר שָׁם כִּי כָבֵד הָרָעָב בָּאָרֶץ  And there was a famine in the land. And Avram went down to Egypt to dwell there as the famine was heavy in the land.

Whatever occurred to the ancestor was a symbol for the descendants. Just as Avraham left Egypt piled high with riches and belongings, so, too, the Jewish nation would be exiled there and leave filled with precious things. 

The Torah used the word לגור to be alliterative with the word גור אריה, a lion cub. He had come there to plunder the sparks of holiness and return them to holiness. Similarly, the exile of the entire nation in Egypt was for this purpose as we find that when they left they emptied out Egypt.

God did not command Avraham to go to Egypt, he went of his own accord because of the famine. The taking of Sara was a punishment in the wake of his choice. However, God agreed with his choice and therefore there was no harm done in the taking of Sara. On the contrary, it led to his receiving much material wealth.