33 The expressions “that it may go well with you” (לְמַעַן תִּחְיוּן וְטוֹב לָכֶם, lemaʿan tiḥyûn weṭôb lākem) and “that you may prolong your days” (וְהַאֲרַכְתֶּם יָמִים, wehaʾaraktem yāmîm) occur repeatedly throughout Deuteronomy. In Deuteronomy, with regard to the nation’s potential fate the former clause occurs with the verb יטב (yṭb) nine times (4:40; 5:16, 29; 6:3, 18; 8:16; 12:25, 28; 22:7) and with the verb טוב (ṭôb) three times (5:33; 6:24; 19:13). The promise of “lengthened” (ארך, ʾrk) days occurs as a positive benefit for the nation in seven passages (4:40; 5:16; 6:2; 11:9; 22:7; 25:15; 32:47) and as something they will not receive because of their disobedience in two passages (4:26; 30:18). These statements occur together four times (4:40; 5:16; 6:2–3; 22:7).
One cannot question that God promises to his chosen nation longevity in the Promised Land and enjoyable life in the wake of covenantal conformity. Is that the ultimate end Yahweh has in mind for his people? In the light of Exodus 19:4–6 and Deuteronomy 26:16–19, where Yahweh commissions his chosen people to represent his character before the surrounding world, these materialistic blessings appear to be immediate objectives rather than ultimate goals. God gave Israel the land of Canaan as a stewardship to provide them with a platform from which they could serve as a witness-nation before the world. Long tenure in the land would give Israel the continued opportunity to carry out their God-given role of demonstrating to the pagan world the awesome and incomparable character of their covenantal Lord.
5:33 — “You shall walk in all the ways which the Lord your God has commanded you, that you may live and that it may be well with you, and that you may prolong your days in the land which you shall possess.”
God gives us His commandments for our good. By keeping them His people gain not only life, but a successful life and a long life.
32–33 The attention now shifts from recollection of past events to present and future obligations. The people are charged to “be careful to do just as YHWH your God commanded you … in order that you may live and … prolong your days in the land.” Moses’ point here is that the instruction received on Mount Sinai came from God himself. This is the word of God and the necessary prerequisite for the blessing “that you may live and it may be well with you” in the promised land.
 Stanley, C. F. (2005). The Charles F. Stanley life principles Bible: New King James Version (Dt 5:33). Nashville, TN: Nelson Bibles.