וַתָּבֹ֖אוּ אֶל־הַמָּק֣וֹם הַזֶּ֑ה וַיֵּצֵ֣א סִיחֹ֣ן מֶֽלֶךְ־חֶ֠שְׁבּוֹן וְע֨וֹג מֶֽלֶךְ־הַבָּשָׁ֧ן לִקְרָאתֵ֛נוּ לַמִּלְחָמָ֖ה וַנַּכֵּֽם׃
너희로 떡도 먹지 못하며 포도주나 독주를 마시지 못하게 하셨음은 주는 너희 하나님 여호와이신 줄을 알게 하려 하심이니라
Rashi
ותבאו אל המקום הזה AND YOU CAME TO THIS PLACE — Now you see yourselves in greatness and glory (you have defeated Sihon and Og); do not rebel against the Omnipresent nor let your hearts be proud, ושמרתם את דברי הברית הזאת BUT KEEP THE WORDS OF THIS COVENANT. — Another explanation of AND THE LORD HAS NOT GIVEN YOU A HEART TO UNDERSTAND [UNTO THIS DAY] — for no-one can fathom the depths of his teacher’s mind nor the wisdom of his teaching until after forty years of study under him. Therefore the Omnipresent has not dealt with you so strictly until this day (after forty years’ instruction of the Torah), but from now and onward He will deal strictly with you — therefore ושמרתם את דברי הברית הזאת וגו׳ KEEP THE WORDS OF THIS COVENANT etc. (Avodah Zarah 5b).
Rabbeinu Bahya
ותבואו אל המקום הזה, “and you arrived at this place.” Moses inserted these two verses in the middle of his lecture as he wanted to reinforce the people’s faith in the fact that they would conquer and inherit the land of Israel, just as they had conquered and inherited the lands formerly belonging to Sichon and Og who also belonged to the seven Canaanite tribes whose land had been promised to the Jewish people (Avraham and the other patriarchs). The two and a half tribes Reuven, Gad, and half the tribe of Menashe had already taken possession of these lands at the time Moses was speaking, leaving the land on the West Bank of the Jordan for the other 9 1/2 tribes.
Rabbeinu Bahya
You should appreciate that the warnings of doom enumerated in this whole portion are Moses’ own wording as distinct from similar warnings of disaster in Leviticus chapter 26. This does not mean that Moses “made up the תוכחה by himself.” Rather, it means that the syntax used by the Torah reflects that G’d approved of the choice of words Moses had used so that effectively everything recorded in the written text of the Torah is equivalent to something dictated by G’d Himself.
If our sages (Megillah 31) stated that the “curses contained in the Torah and which were uttered by the priests were words put in their mouths by G’d Himself,” whereas those contained in the Book of Deuteronomy reflect Moses’ words, they meant that Moses succeeded in voicing thoughts which reflected exactly what G’d would have told him to say.
The reason that the Torah chose to write two versions of these exhortations and warnings, one being G’d’s initiative and words, the other at the initiative of Moses who had divined what G’d wanted him to say, is that the version we read at the end of the Book of Leviticus is that which became true at the time the first Temple was destroyed, whereas the longer version we read here in the Book of Deuteronomy was not fulfilled until the second Temple was being destroyed. One proof that this is so is furnished by the words (Leviticus 26,30) והשמדתי את במותיכם והכרתי את חמניכם, “I will destroy your private altars and demolish your sun-idols.” These are phenomena which existed only during the period of the first Temple when idolatry was widespread among the people during the reigns of many kings. The curses listed in Deuteronomy were all fulfilled during the collapse of the second commonwealth and its Temple.
If our sages (Megillah 31) stated that the “curses contained in the Torah and which were uttered by the priests were words put in their mouths by G’d Himself,” whereas those contained in the Book of Deuteronomy reflect Moses’ words, they meant that Moses succeeded in voicing thoughts which reflected exactly what G’d would have told him to say.
The reason that the Torah chose to write two versions of these exhortations and warnings, one being G’d’s initiative and words, the other at the initiative of Moses who had divined what G’d wanted him to say, is that the version we read at the end of the Book of Leviticus is that which became true at the time the first Temple was destroyed, whereas the longer version we read here in the Book of Deuteronomy was not fulfilled until the second Temple was being destroyed. One proof that this is so is furnished by the words (Leviticus 26,30) והשמדתי את במותיכם והכרתי את חמניכם, “I will destroy your private altars and demolish your sun-idols.” These are phenomena which existed only during the period of the first Temple when idolatry was widespread among the people during the reigns of many kings. The curses listed in Deuteronomy were all fulfilled during the collapse of the second commonwealth and its Temple.