Baal HaSulam, "Inheritance of the Land": And so Abraham wondered, “How will I know that I will inherit it?” meaning how will I know that the Children of Israel will receive such a great reward, since where will they get such big vessels that will be worthy of this wonderful receiving, and to this the Lord answered him, “Know of a surety that thy seed shall be a stranger in a land that is not theirs, and shall serve them, and they shall afflict them four hundred years, and then they will have great exertion in the Torah and the Mitzvot….” This is the case for those who deal with the Torah, but those that deal with the fillings of this world and are not ready to deal with the Torah, how will they receive these vessels? Indeed the answer is that this is what is said in the Midrash, that Israel are not redeemed until they are united…."
So we see that we must connect with the world that provides us its deficiencies because we don’t have enough deficiencies of our own. In the same way we received the desires of the Egyptians in the time of the Exodus from Egypt.
Let’s see how things developed. After the exodus from Babel we went down to Egypt, we were there for 210 years and we went to Mt. Sinai. Then there was a series of ascents and descents until we arrived at the Land of Israel and built the first Temple. Then we fell from that degree and built the second Temple.
Thus we ended the work of the Egyptian exile. We corrected the whole legacy of 210 years in Egypt, all the evil inclination, with the help of the Torah, meaning the method of Kabbalah, which we received on Mt. Sinai.
After having fulfilled this level, we fell, we have been through two thousand years of exile, and now we have to ascend again. It is said about our state that: “The children of Israel were exiled only to add the souls of the gentiles to them," which is all the Babylonians. In the past, Abraham took a small vessel of Israel out of Babel, and now all of Babel have to reach correction. Here, in exile, we meet the Babylonians, we are mutually incorporated in them and together with them rise to correction, as one body that has a "head" and a "body." The head is the point in the heart (*), and the body is what we call "the nations of the world (NW in the drawing)."
Thus we reach mutual correction. The body cannot manage without the head, and the head cannot manage without the body.
From the 4th part of the Daily Kabbalah Lesson 1/20/12, Baal HaSulam, “The Inheritance of the Land”