The two mountains clearly symbolize the concept of life and death, good and evil, for the people. Har Gerizim in full bloom, the symbol of viridity and life, stood in stark contrast to the barren peak of Har Eival, the symbol of desolation and death. The tribes were split into two groups, each taking its position on one of the mountains. The tribes listened to the choices, the blessings and curses, the consequences of good and evil. The people’s acceptance and affirmation of Hashem’s doctrine was, essentially, a renewal of their acceptance of the Torah on Har Sinai.
Horav Eli Munk, zl, distinguishes between the settings of the new covenant and the original circumstances surrounding the giving of the Torah. Now the people were told to stand upon the mountain, as opposed to Har Sinai at which they were told to stand at the foot of the mountain. Rather than accept the law passively, they could now express their sense of conviction confidently, declaring their unshakable resolution to upholding the Torah. They now accepted the Torah actively and were prepared to transmit it to others.
This approach, claims Horav Munk, is the manner of acceptance which every Jew should emulate. We begin by receiving the Torah and inculcating it within ourselves — until that point at which we are prepared to reach out to others, to teach, guide, inspire, and enrich the lives of the next generation. This is the process of mesorah, transmitting the tradition from generation to generation. It is not sufficient for one to remain passive in his acceptance of Torah doctrine. He should go forth, take the initiative and reach out to others. By doing so, every individual Jew expresses his faith in Hashem.