Vayelech recounts the events of Moshe's last day: he hands over leadership to Yehoshua and writes the Torah on a scroll that will be kept in the Ark of the Covenant under the care of the Levites. The mitzvah of "hakhel", gathering all the people to hear the Torah every seven years on Sukkot, is also given here. Ultimately, it is predicted that although the people will go astray, the teachings of God will survive in the mouths of Israel's descendants.
Lo bashamayim hi.
The Torah is not in the heavens. The Talmud illustrates this with a story we have shared before, the story of Taanuro shel Hachnay, Hachnay's oven, in which, during a rabbinical debate, one of the rabbis called upon the heavens as a witness. He said that if he was correct in the discussion they were having, the walls of the yeshiva where they were would lean in; and the walls indeed leaned. Still, no one took his version as true because, in reality, the debate was on Earth, no longer in the heavens.