Genesis 12:1

"Go, yourself" - For your benefit, and for your own good, and there I will make you into a great nation. Here you will not merit children. And what's more, I will let the world know all about you.

AND the Lord said to Abram, Go thou from thy land; separate thyself from thy kindred; go forth from the house of thy father; go into the land which I will show thee.

“Lech Lecha (Go forth)” - God already commanded Abraham, when they were still in Ur Kasdim, to leave his land and country and birthplace and the house of his father. And the reason is that God knew that Terach, after he went to go to the Land of Canaan, would stay in Haran. And Terach did not die until 60 years after Abraham left his house in Haran. But the Torah did not detail all the years after he left Ur Kasdim. And after it says, “that I will show you,” He revealed to him the secret. That’s why it says, in Chapter 11, “They went out to go to the Land of Canaan. Or, the reason it says "I will show you" is that He is saying, "All the land that you can see, I will give you."

AND THE ETERNAL SAID UNTO ABRAHAM ‘LECH LECHA’ (GET THEE OUT). This means, “For your own benefit and for your own good. And there I will make of you a great nation whilst here you will not merit the privilege of having children.” Thus the language of Rashi.
Now there is no need for it (literally, “to you”) as meaning “for your own benefit” for it is merely the idiomatic usage of the Hebrew language, as explained further in the text. for such is the normal expression of the Hebrew language as in the verses: The rain is over and gone ‘lo’; I will get ‘li’ unto the great men; Rise up, and get ‘lachem’ over the brook Zered; and many similar examples. Our Rabbis, however, have made a Midrash — (a homiletical interpretation) — concerning the verses [addressed to Moses] which state, And thou shalt make ‘lecha’ an ark of wood,, meaning Moses, but in Exodus (25:10) it states, And ‘they’ shall make an ark! This teaches us that the people of a community are commanded to do the work of a Torah-scholar who resides in their midst.” (Yoma 72b.) and Make ‘lecha’ two trumpets of silver, since it was not his work and it would have been proper for these verses to be stated in the same way as that concerning the tabernacle, i.e., And thou shalt make the tabernacle.

אל הארץ אשר אראך, to the specific area within the country which I will show you in a heavenly vision. This is why Avram kept moving further into the land without pitching his tent to settle down until he received the appropriate sign from G’d. This occurred when he reached Shechem, where we are told that G’d appeared to him (verse 7)

ויאמר ה' אל אברם לך לך מארצך וממולדתך ומבית אביך אל הארץ אשר אראך, in this instance the word ויאמר refers to something G’d had already said to Avram before he had even moved away from Ur Casdim, a move he made at the command of G’d. We know this from Genesis 15,7 where G’d reminds him that “I am the Lord Who has taken you out of Ur Casdim.” It is possible that G’d repeated this directive once more while Avram was in Charan. As to the meaning of the word lecha, i.e. “for your own good,” this does not have any special significance, being a commonly used figure of speech. One example would be Exodus 18,27 וילך לו where Yitro’s return to Midian is described in a similar way, and no one suggests that he did so “for his own good.” Another such example is found in Jeremiah 5,5 אלכה לי, “I am going,” where no one suggests that Jeremiah had ulterior motives in going to the wealthy people to speak to them in the belief that they knew the ways of the Lord. Still other examples of a similar construction are found in Numbers 22,34 אשובה לי or in Genesis 45,19 קחו לכם.

מארצך, G’d had to add this as it is difficult for a person to leave a homeland in which he had dwelled for many years, all the more so if that land was at the same time the place where he had been born. This is why G’d added: וממולדתך, since it is doubly difficult to separate from one’s family also and to go to a country where one knows no one. This is the meaning of מבית אביך, “away from your father’s house.”

אל הארץ אשר אראך, if G’d had told Avram that He would show him a land which was rich, fertile, good, etc., it would not have been as difficult to comply with such a directive. But the fact that G’d did not add these inducements made it more difficult for Avram to decide. The reason why G’d did not offer these inducements was to show us, the readers, how great was Avram’s love of G’d that he unquestioningly abided by what G’d had asked him to do. He was determined to carry out the wishes of his G’d.