"That your days may be multiplied, and the days of your children, in the land which the LORD sware unto your fathers to give them, as the days of heaven upon the earth." (Deuteronomy 11: 21)
When we read the passages in the Old Testament, we must accept that the commands to the Israelites of those days are not for us today.
In that same chapter, for example, God says to His chosen people:
"26Behold, I set before you this day a blessing and a curse; 27A blessing, if ye obey the commandments of the LORD your God, which I command you this day: 28And a curse, if ye will not obey the commandments of the LORD your God, but turn aside out of the way which I command you this day, to go after other gods, which ye have not known." (Deuteronomy 11: 26-28)
Today, because of Jesus, there is no curse:
"13Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed is every one that hangeth on a tree: 14That the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith." (Galatians 3:1 3-14)
Notice that Paul writes about the blessings of Abraham coming on the Gentiles, not the curses.
While many well-meaning church people would contend that the promises accorded to Abraham do not count, either, Paul corrects that misunderstanding, too:
"13For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith. 14For if they which are of the law be heirs, faith is made void, and the promise made of none effect: 15Because the law worketh wrath: for where no law is, there is no transgression." (Romans 4: 13-15)
"Know ye therefore that they which are of faith, the same are the children of Abraham." (Galatians 3: 7)
Because Jesus has freed us from the curse of the law, by being the Curse for us on the tree and fulfilling the condemnation in Himself for us, we can expect nothing but Heaven on Earth.