When God made the promises to Abraham back in Genesis 12, He told him a few things. First, that He would give His descendants the land of Canaan. Second, that they would be a great nation. And three, that through his descendants, all the nations would be blessed.
The first of those promises is about to come true (land). The second one (great nation) is in process, and the third promise wouldn’t be fulfilled until the coming of the Messiah.
It must’ve been an exciting time for the Israelites. Already their numbers have swelled from an admirable 70 people (when they left Canaan and went to Egypt with Joseph) to a number most likely over two million (Numbers 26).
That number will grow even more in time, but now that they’re about to take the promised land, they should be able to see the fact—which Moses constantly reminds them of—that God keeps His promises.
Even the phrasing here in Deuteronomy 7:12 should sound familiar. It’s nearly word for word what God tells Abraham in Genesis 22:16-18 when He restates the promises after Abraham almost sacrifices Isaac.
By the way, has it occurred to you yet that Moses isn’t even speaking about the conquest itself, which they still have to do if the want to even occupy Canaan? To him, that’s a given; Deuteronomy assumes they will be victorious because God is on their side.
The blessings themselves are contingent upon obedience. Moses has made this plain several times, but the degrees of these promises are noteworthy. There won’t be any sickness, no barrenness, and no enemies to speak of. It’s a utopia, in other words.
Does God actually mean that? Assuming the nation of Israel is able to keep every commandment perfectly, would no one ever even catch a cold?
Not exactly. Since Moses calls to mind Egypt in Deuteronomy 7:15, the real takeaway here is that the nation at large won’t be punished as the enemies of God will. Egypt stood against God and lost. If Israel stands with God, they can expect to avoid those types of calamities.
But I also think there’s an element of practicality to all this as well. The law contains instructions that are very reasonable: Don’t attack apex predators (Leviticus 11), make sure you clean your bodies after touching a corpse (Leviticus 15), and keep waste outside the camp (Deuteronomy 23:12-13).
It shouldn’t take a rocket scientist to see that if you don’t try to eat a crocodile and keep your toilets away from your eating area, you’ll probably stay healthier than you would otherwise.
It’s fair to say that some of these laws are put in place because of ritual purity, but that others just speak to an understanding of how the world works. God had that knowledge, but it’s likely not everyone did.
This is how God blesses people. It’s not always through divine intervention (although He certainly did with Israel). Most of the time though, a life lived according to God’s rules just turns out better than one that doesn’t.