In the Zohar (Noach, Chapter 13, Verse 89) we find the following:
וְאִלְמָלֵא דְהָדְרוּ יִשְׂרָאֵל וְחָאבוּ קַמֵּיהּ קֻדְשָׁא בְּרִיךְ הוּא, לָא הֲווֹ מֵתִין לְעָלְמִין, דְּהָא אִתְפַּסַּק מִנַּיְיהוּ זוּהֲמָא דְנָחָשׁ. כֵּיוָן דְּחָבוּ, כְּדֵין אִתְבָּרוּ אִינוּן לוּחֵי קַדְמָאֵי, דַּהֲווֹ בְּהוֹ חֵירוּ דְּכֹלָּא, חֵירוּ דְּהַהוּא נָחָשׁ, דְּאִיהוּ קֵץ כָּל בָּשָׂר.
And had Yisrael not sinned before the Holy One, blessed be He, they would have never died, for the pollution of the serpent had been purged from them. But because of their sin, the first tablets, which brought freedom from all sins, freedom from the serpent - who is "the End of all Flesh" (THE ANGEL OF DEATH) - were broken.
It states that if the Jews hadn't committed the sin that caused the first set of Tablets to be broken, then they would have never died.
Does anyone know if this lack of death would have applied to non-Jews also? Would the gentiles have lived forever too, after Matan Torah?