Yevamot 2 - 8
Rav Yosef, said, “Even the Tana who is of the opinion to not learn from “semuchin” (juxataposed ideas) in the rest of the Torah — in Sefer Devarim, however, he agrees that semuchin are a legitimate method to learn something new.”
What’s the difference between Sefer Devarim and the rest of the Torah? There are two opinions in Shas as to how the Torah was “given”: all at once, or a scroll at a time (Gittin 60a). If the Torah was given and told to the Jewish People all at once, then it would be permitted to learn semuchin everywhere throughout the Torah. If not, however, it is not — with the exception of Sefer Devarim which was all given and told to the Jewish People by Moshe all at one time at the end of the 40 years in the desert. Since it has the nature of “one unit”, so to speak, it is fair to learn semuchin in this section, since unlike the other parts of the Torah it was all told and given together. (Maharitz Chiyut)
- Yevamot 4a
Our Sages taught in a beraita, "The same passage in the Torah commands to keep Shabbat and to show respect to the Beit Hamikdash Sanctuary (Lev. 19:30), in order to teach that just as Shabbat observance is forever, so too we must show respect to the site of the Beit Hamikdash even after the building has been destroyed."
- Yevamot 6b