This parashah begins by describing how the new generation, the one born in the desert, renewed the covenant with God that Abraham had made for himself and his seed (Genesis 17: 3-7), which Isaac sustained (Genesis 26: 2-5), and Jacob continued (Genesis 35: 9-12).
God had already made a pact with the Children of Israel as a people when they left Egypt, then again at Sinai in giving them the Torah, and finally in this parashah (Midrash Tanchuma, Nitzavim, 6).
This time, God does not only covenant with those present, but also with all their future generations (See Rashi and Seforno on Deuteronomy 29:14). Each generation was able to renew the covenant. The Bible describes how it was renewed in the times of Joshua (chapter 24) and later in the days of King Josiah (II Kings 23).
The covenant substantially consists in the people agreeing to live according to the principles set forth in the Torah and God agreeing to bless and protect the people.
Tradition teaches us that this parashah must always be read before Rosh Hashana (Shuljan Aruj, Oraj Jayim 428.4), given that in the first ten verses of chapter 30, the verb ShUV, return, in the sense of returning to God or modifying wrong attitudes in our lives, is often repeated.
They stress teshuva, contrition and reform, one of the essential elements of Rosh Hashana. Fittingly, we also find in these verses the idea of God's returning to the people who know how to turn back to Him.
The idea of covenant and how to better observe its terms is the reflection with which the individual Jew and the Jewish people begin each new year.