Yup, eventually believers reach the same stopping point but instead of saying "I don't know" they go "God did it", until science explains how that happened, so believers go to the next thing and say "well I don't know how this happened, therefore God". That is called "the God of the gaps" and it's a terrible argument, it's okay to admit we don't know something.
And no, I'm not talking about Abraham, I'm talking about Jesus, the whole reason why Jesus is crucified is so that his blood can clean the sin of mankind. The basics of Christianism are the following tenets:
- God can't (or doesn't want to) coexist with Sin
- God requires blood sacrifices, usually animals, to purify Sin
- God offered a loophole, by sacrificing an innocent person anyone can point at that sacrifice and say "I'm using this sacrifice to purify my sins".
- Because there are no Sinless humans he had to come down in human form to sacrifice himself so that he could charge the innocent blood price for the Sins of mankind
Otherwise why would God need to offer himself as sacrifice to purify sins? Couldn't he just say "all sins are gone"? However you look at it he asks for a blood sacrifice, however he allows you to cash in his own blood sacrifice in its place, and if you don't he sends you to Hell, very loving fellow.