רַבִּי אוֹמֵר: בְּשָׁעָה שֶׁעָמְדוּ יִשְׂרָאֵל עַל הַר סִינַי, הִשְׁווּ כֻּלָּן לֵב אֶחָד לְקַבֵּל עֲלֵיהֶם מַלְכוּת שָׁמַיִם בְּשִׂמְחָה, שֶׁנֶּאֱמַר: וַיַּעֲנוּ כָל הָעָם יַחְדָּו וַיֹּאמְרוּ. וְלֹא עוֹד, אֶלָּא שֶׁהָיוּ מְמַשְׁכְּנִין עַצְמָן זֶה עַל זֶה. בְּאוֹתָהּ שָׁעָה בִּקֵּשׁ הַקָּדוֹשׁ בָּרוּךְ הוּא לִכְרוֹת עִמָּהֶן בְּרִית עַל הַסְּתָרִים וְעַל הַגְּלוּיִים. אָמְרוּ לוֹ: עַל הַגְּלוּיִים אָנוּ כּוֹרְתִין וְלֹא עַל הַסְּתָרִים. שֶׁלֹּא יְהֵא אֶחָד חוֹטֵא בַּסֵּתֶר וִיהֵא הַצִּבּוּר מִתְמַשְׁכֵּן עָלָיו, שֶׁנֶּאֱמַר: הַנִּסְתָּרֹת לַה' אֱלֹקֵינוּ וְגוֹ' לַעֲשׂוֹת אֶת כָּל דִּבְרֵי הַתּוֹרָה הַזֹּאת (דברים כט, כח) לְפִיכָךְ, וַיְדַבֵּר אֱלֹקִים אֶת כָּל הַדְּבָרִים.
Rabbi said: At the hour that Israel stood at Mount Sinai, all agreed with one heart to receive with joy the yoke of the Kingdom of Heaven, as it is said: And all the people answered together, and said... (Exod. 19:8). And what is more, they pledged themselves in behalf of each other. At that hour the Holy One, blessed be He, sought to create a covenant with them concerning the hidden and revealed matters, they said: We will covenant with You concerning the revealed matters, but not concerning that which is hidden, so that if one of us sin in secret, the entire congregation will not be pledged for him, as it is said: The concealed things belong to Ha-shem our God; but the things that are revealed belong unto us, etc. (Deut. 29:28), in order that we may perform all the words of this law. Therefore, God spoke all these words.
כתנאי (דברים כט, כח) הנסתרות לה' אלקינו והנגלות לנו ולבנינו עד עולם למה נקוד על לנו ולבנינו ועל עי"ן שבעד מלמד שלא ענש על הנסתרות עד שעברו ישראל את הירדן דברי ר' יהודה
א"ל ר' נחמיה וכי ענש על הנסתרות לעולם והלא כבר נאמר עד עולם אלא כשם שלא ענש על הנסתרות כך לא ענש על עונשין שבגלוי עד שעברו ישראל את הירדן...
[Among the Tannaim, they discussed the verse] The concealed are Ha-shem our God's and the revealed are ours and our children's forever /ad olam. Why are there dots above [the words in the Torah] ours and our children's and over the 'ayin of 'ad/forever? This teaches that He did not punish for concealed [sins] until Israel had crossed the Jordan, according to the words of R. Yehudah. R. Nehemiah said to him: And did He ever punish [the whole nation] for the concealed [sins of the individual]? Did it not already say [the concealed {sins of the individual}] belong to Ha-shem our God] 'ad 'olam/forever? But rather just as He did not punish [the whole nation] for the concealed [sins of individuals], so also He did not punish [the whole nation] for [sins of the individual] in the open until Israel crossed the Jordan.
וְדִכְוָתָהּ (דברים כט, כח): הַנִּסְתָּרֹת לַה' אֱלֹקֵינוּ וְהַנִּגְלֹת לָנוּ וּלְבָנֵינוּ עַד עוֹלָם, לָמָּה נָקוּד עַל לָנוּ וּלְבָנֵינוּ וְעַל עי"ן שֶׁבְּעַד, אָמַר לָהֶם עֲשִׂיתֶם גְּלוּיִם אַף אֲנִי אוֹדִיעַ לָכֶם אֶת הַנִּסְתָּרוֹת....
...And similarly: The concealed are for Ha-shem our God and the revealed are for us and our children forever/ 'ad olam (Dvarim 29:28). Why are there dots over "for us and our children" and over the 'ayin that is in 'ad ? He said to them, You have done the revealed [sins]; certainly I will make known to you the concealed ones...
...The people of Israel have a collective responsibility, both halakhic and moral, for one another. The discrete units coalesce into a single halakhic-moral unity, with one all-encompassing and normative conscience and consciousness. The halakhah has already decreed that “all Jews are sureties for one another” (TB Shavu’ot 39a), such that one who has already fulfilled his personal mitzvah is not considered fully absolved thereby and may therefore fulfill the obligation on behalf of others who have not as yet done so. The “I” is not exempt from its obligation so long as his neighbor has not fulfilled that which is incumbent upon him. There is a special covenant of mutual responsibility among the children of Israel. This covenant is expressed in the blessings and imprecations pronounced on Mounts Gerizim and Ebal (Deuteronomy 11:29). It is based upon the notion of peoplehood revealed to Moses in Egypt. Out of this concept grew the covenant of mutual obligation. Moses, the dean of all prophets, in relating this covenant of mutual obligation, emphasized: “For that He may establish you today unto Him as a people, and He shall be unto you as a God” (Deuteronomy 29:12). He thus returned to the formulation of the Covenant of Egypt. “And I will take you to Me as a people, and I will be your God” (Exodus 6:7). Here the notion of shared fate was elevated from the plane of communal-political suffering to that of halakhic and moral responsibility. We are all sureties for one another, as it is said: “And the revelations belong to us and to our children forever” (Deuteronomy 29:28).12