We are coming to the end of the Torah. Moses has been commanded by God to die. Moses finishes his oration by telling the people that they will pass the Jordan River and enter into the land, succeed in conquering the land under Joshua's leadership, and will find a place (מָּקוֹם in Hebrew) where the Temple will eventually be built. The zeal of the people will eventually slacken, and they will begin to worship other gods, and this will offend the Lord, who will expel them from the land and beset them with curses.
To guard against this, Moses has composed a song which every Hebrew child is to memorize (the lyrics will be in the next Torah portion, the penultimate one) that will remind them to stay faithful. Once the Israelites are exiled from the land and cursed, they will still remember the song, and know why they are being punished.
Moses emphasizes the importance of the Law. He writes the Law down in a Torah scroll and orders that, once the Temple is built, it should be read out loud in its entirety in public in front of the Temple every seven years during the start of the Sabbatical Year. The books of Chronicles and Kings record that this practice stopped happening somewhere along the way, and the corrupt kings of Israel and Judah ruled in ignorance of the Law. Second Chronicles tells us that during the reign of Josiah, King of Judah, the Temple was renovated, and in a secret place celebrated by Royal Arch Masons, found a scroll with the Law written on it. [2 Chronicles 24: 14-19]. Previous to which, it had been lost to the Children of Israel. Josiah dedicated the rest of his reign to enacting the laws found in the scroll.
Something similar happens after the return to Israel after the Babylonian Captivity. After the Second Temple is built by Zerubbabel, the Scribe Ezra gathers the people and reads them the entire Torah. The whole nation wept in dismay for having forgotten the Torah. [Nehemiah 8: 9]. The efforts of Ezra and Nehemiah were devoted to keeping the laws of the Torah in the newly rebuilt kingdom.