In its literal or plain meaning, the verse means that God's commands are not overwhelming but rather close to human hearts and abilities to obey. As noted in the New Oxford Annotated Bible, "The covenant demand is not beyond human reach or understanding but has been graciously revealed... 'the word is near you.'" The full verse states: "It is not in heaven, that you should say, 'Who will go up to heaven for us, and get it for us so that we may hear it and observe it?' In general, the verse conforms with how "... the deuteronomic tradition believed its Torah to be an immediately accessible wisdom, neither distant nor wondrous."
The phrase "not in Heaven" is understood to justify human authority to interpret the Torah. The Talmud explains "[The Torah] is not in Heaven" to mean that the meaning of the Torah itself is to be uncovered not by prophets, or even God's miracles or words, but by humankind's interpretation and decision-making. In the story of the Oven of Akhnai, "Rabbi Yehoshua affirmed the independence of human interpretation from divine intervention since this is what God wills. In support he adduces the biblical statement that the Torah is 'not in heaven' (Deuteronomy 30:12)."
In the academic study of Jewish law, the verse "not in Heaven" serves as the Biblical grounding for the jurisprudential structure of halakhah (Jewish law). The source for Rabbinic authority is really from Deuteronomy 17:11 (According to the law which they shall teach you, and according to the judgment which they shall tell you, you shall do). As one author explains, thanks to the midrashic reading of the verse, "...God himself acquiesced in His exclusion from the halakhic process. Having revealed His will in Sinai in the grundnorm, He Himself, according to the Rabbinic explanation, entrusted the interpretation of His will to the Sages."