He was also stabbed with a spear (which indeed is much more famous, never heard of the whip that whipped Christ before). But I guess you can always say... Bloodlines had a spear heh.
Yes there was a spear, but Jesus was also whipped by the Romans prior to being put on the cross. While on the cross he was stabbed just under his ribs to pierce a lung. (Possibly to kill him faster, you die from lack of oxygen when crucified. Though historically he was more likely crucified to a tree then a cross.) The whip was used of course as torture. It was meant to tear apart the flsh on ones back. By the time it's use is over, it's likely left your skin in a shredded tatters.
Whips are thus a very punishing weapon. But they are hard to control, require much skill, and was widely used once up until christianity took over europe. I
Besides, the whips in Castlevania are pretty badass compared to other games and stories. We've seen the clasic leather whip, the chain whip. The morning star Vampire killer, which is a chain wjip with a mace at the end. The fire whip, rose whipe of thorns, and so much more. Props to Konami for doing something original.
Personaly, I want to see more weapon options. If you use the whip, then you should be able to use other weapons too. I don't understand why Belmonts can only use the whip and subweapons, but other characters can use a lot of diverse weapons. It makes sense for a Belmont to at least carry a short sword with them. And no the throwing knife doesn't count. C64 had the right idea in it's weapon use, it just needed bettter execution.