The Jews were assembled on two mountains, Grizim and Eival, for blessings and curses contingent on their observance of the Torah. The tribes were split and ascended the respective mountains as instructed. The people on each peak then answered in unison to the other peak, in a kind of very loud conversation spanning mountains:
אֵלֶּה יַעַמְדוּ לְבָרֵךְ אֶת-הָעָם, עַל-הַר גְּרִזִים, בְּעָבְרְכֶם, אֶת-הַיַּרְדֵּן: שִׁמְעוֹן וְלֵוִי וִיהוּדָה, וְיִשָּׂשכָר וְיוֹסֵף וּבִנְיָמִן. וְאֵלֶּה יַעַמְדוּ עַל-הַקְּלָלָה, בְּהַר עֵיבָל: רְאוּבֵן גָּד וְאָשֵׁר, וּזְבוּלֻן דָּן וְנַפְתָּלִי – These tribes will ascend to bless the people, from Har Grizim, (…), and these are the tribes that will ascend for the curse, on Har Eival (…). (27:12-13)
The instructions are not identical. The people blessing ascended “to bless” actively – יַעַמְדוּ לְבָרֵךְ אֶת-הָעָם, whereas the people answering curses ascended “for the curse” – יַעַמְדוּ עַל-הַקְּלָלָה – passively. Why the disparity?
The Kli Yakar explains that curses can only only result from human action. The nature of reality is that all order disintegrates into chaos; and God protects people from this. If people create a distance between themselves and God, bad things may well happen, but it is not a new reality; rather it is due to their protector being masked. The lack of blessing is the curse. When a person feels a distance between them and God, it is not God who has gone anywhere.
But this is not a fixed situation. In Moshe’s opening words to the people at the mountains, he says:
הַיּוֹם הַזֶּה, ה אֱלֹהֶיךָ מְצַוְּךָ לַעֲשׂוֹת אֶת-הַחֻקִּים הָאֵלֶּה–וְאֶת-הַמִּשְׁפָּטִים; וְשָׁמַרְתָּ וְעָשִׂיתָ אוֹתָם, בְּכָל-לְבָבְךָ וּבְכָל-נַפְשֶׁךָ – On this day, Hashem your God commands you to keep these statutes and laws, and you will guard them and perform them, with all your heart and soul. (26:16)
This is monumental in its context, but equally so today. Rashi notes the use of the present tense; indicating that the same obligations exist every day, no different to the day the Torah and mitzvos were first accepted.
The curse, or lack of blessing, is dynamic. Anything can change, so the commitment has to be constantly fresh – הַיּוֹם הַזֶּה – today is a new day. Be all you can be.