Deuteronomy 30 anticipates both exile and restoration. When all these things had come upon Israel, both blessing and curse, they could call them to mind among the nations and return to Yahweh with all their heart. God would then release them from captivity, have compassion, and gather them even from the farthest parts under heaven. Most importantly, Yahweh your God will circumcise your heart. This promise anticipates the new covenant of Jeremiah 31 and Ezekiel 36, fulfilled through the Spirit (Romans 2:29).
Moses insists that God's command is not too hard or too distant. It is not in heaven, nor beyond the sea, that someone must fetch it. The word is very near you, in your mouth and in your heart. In Romans 10:6-10 Paul applies these lines to the gospel. Christ has come down and been raised, so the righteousness of faith says the word is near: confess Jesus as Lord and believe in your heart.
Calling heaven and earth as witnesses, Moses sets before Israel life and death, blessing and curse, and pleads, Therefore choose life, that you may live, you and your descendants. Choosing life is relational: to love Yahweh, obey His voice, and cling to Him, for he is your life, and the length of your days. The choice was real, and God's grace made it possible.