On the last day of Moshe’s life, he tells Bnai Yisrael that he knows that they are frightened after he had just finished telling them about the ninety-eight different curses that could potentially befall them. Moshe then comforts them by saying that Bnai Yisrael will survive and that all of the curses will come back to help them. In 32:23, the Torah says “I shall spend My arrows on Am Yisrael.” This threat is also a comfort, for it implies that all My arrows shall be spent but Bnai Yisrael will still be here. There is a fable regarding this quote: An archer aimed his bow at the ceiling. He continued to shoot until he had run out of arrows. After he had shot all of these arrows, miraculously the ceiling had survived. Similarly the Jewish people suffer and many members of Am Yisrael die. However after all of these assaults and losses Am Yisrael ultimately survives.
Moshe then says, “This day resembles the day of the giving of the Torah. G-d is entering with you into a new covenant, to which He binds you with an oath.” Moshe is saying here that everyone, including the converts, who are entering into this covenant must learn and fulfill the Mitzvot of the Torah. Why would Moshe be talking about the future when the people he is talking to will not be experiencing the actual entering of Eretz Yisrael? It is similar that at Matan Torah the souls of the future generations were at the assembly listening to Moshe so that when their time came to fulfill the Mitzvot they would know the importance of them. After all of the curses were told to the Bnai Yisrael of present and the Bnai Yisrael of the future why did Hashem have Moshe make Bnai Yisrael take another oath if everyone had already taken one at Matan Torah? It is because Bnai Yisrael had been isolated in the desert for so many years. They survived because they got all the help they needed from Hashem. So much so, that Bnai Yisrael started to rely on Hashems powers and not worry about surviving for themselves. Hashem thought that only reason Bnai Yisrael kept the Torah was because of the miracles not because they had a love for it and Hashem. So, Hashem had Bnai Yisrael take another oath before going into Eretz Yisrael since there was a great danger that once Bnai Yisrael entered Eretz Yisrael since they would become more lazy when it came to keeping the Mitzvot.