Way back in Genesis, God promised Abraham He would make his descendants as numerous as the sand on the seashore and bless them with land. Here we see both of those promises kept. In addition, we are told of Solomon’s wealth and wisdom.
God will always do what He promises; not always as soon as we would like, but He will do it. I’m sure Abraham wasn’t expecting 400 years of slavery to accomplish it, but that was God’s plan.