It seems that the source for this understanding that the song proclaims the future redemption of the Jewish people is from the last three words of the song, 32:43, "Effecting atonement for the soil of His people," Fox translation, 1995, p.1007. The idea of the verse is that G-d will punish the people who attacked the Jewish people, and this will expiate the land of Israel, see Rashbam on 32:43. However, if the song proclaims the redemption of the Jewish people, then the verse is understood to mean that when G-d will punish the nations who attacked the Jewish people, this would also lead to atonement of the Jewish people, and not just the land of Israel, see Hizkuni and Seforno on 32:43.
Ibn Ezra (on 32:43) explains that this reading is based on adding a "vav" to the last word of the song, which then would change the last words of the song to be "effecting atonement for the soil and for His people." Ibn Ezra rejects this "textual emendation," but instead suggests that the end of the song should be understood that it will be the Jewish people who punish their enemies in the land of Israel, which then could be understood as meaning that the Jewish people would be redeemed. Bekhor Shor (on 32:43) offers a different reading with the same outcome. He writes that when the land attains atonement, then this means that the people are also atoned, and this will be in the messianic age.
These readings of the last three words are a thin basis to claim that the song proclaims the redemption of the Jewish people. The simple reading of 32:43 is like the Rashbam that only the land will attain atonement and not the people. Furthermore, is atonement the same as redemption? The verse only refers to destroying the enemies of the Jewish people, but does this mean that the Jewish people would prosper? Finally, one would think that if the point of the song was to teach the people about the future redemption, then this would have been mentioned unambiguously in the song, and not just cryptically in the last three words of the song.
I believe that the point of the song is stated very clearly in the beginning of the song in 32:4. The verse states, "The Rock, whole and perfect are His deeds, for all His ways are just. A G-d steadfast, (with) no corruption, equitable and upright is He," Fox translation. According to this verse, the point of the song is to explain that G-d's ways are just and that G-d punishes each nation according to what it deserves.
32:5 explains that it was the Jewish people who were corrupt and that is why they were punished. The song then amplifies on this idea, by recalling how initially G-d was good to the people, 32:6-14. However, the people forgot G-d and worshipped idols, 32:15-18. Thus, it was the people's behavior who caused G-d to punish them, 32:19-25. The nations that attacked the Jewish people will not recognize G-d and then G-d will punish them for having attacked the Jewish people, 32:26-43. This punishment of the other nations is considered as a vindication of the Jewish people, 32:36,43, but I believe that nothing is said of the Jewish people being redeemed in the song. Instead, the song stresses how the Jewish people and the non-Jewish nations are being punished for their sins, which is the "fulfillment" of 32:4.
Bibliography:
Fox, Everett, 1995, The Five Books of Moses: A new translation, New York: Schocken Books.
Leibowitz, Nehama (1905-1997), 1982a, Studies in Devarim, translated and adapted by Aryeh Newman, Jerusalem: The World Zionist Organization.
These readings of the last three words are a thin basis to claim that the song proclaims the redemption of the Jewish people. The simple reading of 32:43 is like the Rashbam that only the land will attain atonement and not the people. Furthermore, is atonement the same as redemption? The verse only refers to destroying the enemies of the Jewish people, but does this mean that the Jewish people would prosper? Finally, one would think that if the point of the song was to teach the people about the future redemption, then this would have been mentioned unambiguously in the song, and not just cryptically in the last three words of the song.
I believe that the point of the song is stated very clearly in the beginning of the song in 32:4. The verse states, "The Rock, whole and perfect are His deeds, for all His ways are just. A G-d steadfast, (with) no corruption, equitable and upright is He," Fox translation. According to this verse, the point of the song is to explain that G-d's ways are just and that G-d punishes each nation according to what it deserves.
32:5 explains that it was the Jewish people who were corrupt and that is why they were punished. The song then amplifies on this idea, by recalling how initially G-d was good to the people, 32:6-14. However, the people forgot G-d and worshipped idols, 32:15-18. Thus, it was the people's behavior who caused G-d to punish them, 32:19-25. The nations that attacked the Jewish people will not recognize G-d and then G-d will punish them for having attacked the Jewish people, 32:26-43. This punishment of the other nations is considered as a vindication of the Jewish people, 32:36,43, but I believe that nothing is said of the Jewish people being redeemed in the song. Instead, the song stresses how the Jewish people and the non-Jewish nations are being punished for their sins, which is the "fulfillment" of 32:4.
Bibliography:
Fox, Everett, 1995, The Five Books of Moses: A new translation, New York: Schocken Books.
Leibowitz, Nehama (1905-1997), 1982a, Studies in Devarim, translated and adapted by Aryeh Newman, Jerusalem: The World Zionist Organization.