The Israelite's commonly referred to the temple as heaven and earth, which was destroyed a "generation" later exactly as Jesus predicted in 70AD by the Romans.
In order to understand why the Jews did what they did in the Old Testament, and seemingly wiped out other people, you have to understand the covenants they made with God. There is a very, very interesting event that occurs in Exodus 19 that would forge how the Israelite's operated for the next many centuries. Prior to this event, God had forged what is called a "Grant Covenant" between Him and those who believed in Him. This is a covenant style that protects the relationship, and an example of a common grant covenant is, say, your relationship between yourself and your mother or father. Fresh out of slavery though, which was their identity, the Israelite's don't understand this. In Exodus 19 God invites them up to the mountain after the long blast of the ram's horn, and they don't come. They think God is scary, and they basically state, "Just give us rules and laws that we can follow, and we'll do that instead." The story is more complex than that, but that's what happened. And so because of those events, while God wanted to forge a Grant Covenant and "Bless the nations because of you," the Israelite's instead chose to forge a Parity Covenant with God. This is a common covenant that is forged between two people, peoples, or nations where the laws by which they abide by are duplicated on two stones or scrolls, and they each go their separate ways where their "god" enforces both sides. Common examples of a parity covenant are trade agreements, NATO, etc. And when two people come into parity covenant, the enemies of one become the enemies of the other, and this pitted God against the Israelite's enemies. God chose to enter into this covenant because it was the only way to have some sort of relationship with the Israelite's (they didn't understand, and they didn't want to be in grant covenant with God), but it was never God's heart. His heart was always to be in covenant of that of a father/son relationship, and prior to this, His relationship with humans was always just that.
And centuries later, Jesus came to abolish this and re-establish the proper covenant with mankind. In Luke 15, the story of the parable son, this is an example of just that. God's heart was NEVER to be in parity of vassal covenant. It is not God's heart to ever control us, to lay down tons of rules and say, "Obey, or else!". It is always to be in relationship of that of a Father/Son/Daughter.
So if you're ever wondering why Jesus came, or why the Israelite's wiped out babies and seemingly did some pretty rotten things, that's why. When Jesus died on the cross, he made the old covenant obsolete just as he described. A generation later, that "covenant" was completely destroyed. And since then, the "Kingdom of God" has been expanding across the earth, but it is not a physical one, it's a spiritual one.