Oh, you'll be interested when you get going!
The doctrine that the Bible has 2 peoples and 2 programs was developed by Dispensationalism. Ryrie at Dallas TS said 'it is the definitive doctrine of D'ism.'
It says that at Gen 12 or so, a separate program of God with a separate way of worship, of having faith, of salvation, of law, of location, of existence went into effect, and which still has unfinished business.
The initial one was 'just for gentiles' and 'salvation' is eternal life elsewhere.
So unless you really like your Bible to be schitzophrenic, you'll care quite a bit whether there is any truth to 2P2P.