The Rebbe taught this discourse on Shabbat Lech Lecha in 1964. G-d tells Abraham to 'go to yourself' - go to the root of your soul. The discourse explains that one way to do this is by entering a more holy realm, going to the Land of Israel. The other way is to bring holiness into the non-holy realms. Abraham sharing his inspiration with those who do not yet believe in one G-d.