Some people are disputing it, fwiw. But one thing is clear: the Passover lamb was not killed to atone for anyone's sins. The Jews use a goat for that purpose and that happens on Yom Kippur, which is nowhere near the Passover.
Again, animal sin offerings were for involuntary sins only, which is a big fly in the Christian ointment.
As for the Tanakh, the book of Isaiah which is found in the oldest known Tanakh (9th century AD, Moscow), and all subsequent copies of it, agree fully with the Qumran version of Isaiah.
Some may dispute whether a lamb or a ram, but all depictions on Egyptian imagery, pyramids etc. are of a ram, with horns. There is no sacred lamb in Egyptian imagery, nor in the egyptian religion.
More importantly, Christianity literally turned some OT stories upside down. .... The lamb was clearly not killed to "atone" for any iniquities, as the Christians teach."The Church does not teach that the lamb was killed during Passover to atone for any iniquities.
Lev 5:1-4 describes sacrifices for wilful sins.
Likewise, the shedding of the blood for atonement applied only for unintentional sins. In Judaism the sins of willful commission could not be atoned by animal sacrifice, but only through repentance. Obviously the Christians "corrected" that too!
Besides, the sacrificial animal had to be killed on the altar, and its blood sprinkled. Crucifixion was no altar sacrifice and Jesus bleeding all over the place from Roman torture and being nailed to the cross was hardly ritual "sprinkling.The altar sacrifice imagery is what we see in Revelation, more as a view from heaven, or a "higher altar". Ritual "sprinkling" is explained more as the way in which the Eucharist is sprinkled throughout the world, since the Eucharist IS the self-same ONE-time sacrifice and Christ's blood is sprinkled as in spread throughout by the effectiveness of the Eucharist.