And what is the purpose of it?
What is the purpose of a chunk of granite or a dinosaur or poison ivy? You’re asking silly questions.
And what is the purpose of it?
To know Jesus, the creator of both. To back his claims as creator, he performed numerous miracles, rose from the dead, and made numerous prophecies about his own death and resurrection. Of his 12 disciples, who were in the position to KNOW if his claims were true or not, 11 died professing it's veracity, and the last on died in exile. BTW, the "sect" of Christianity grew in the very city where he was crucified and resurrected, adhered to by people who would KNOW if the whole thing was a sham. The historical evidence is compelling, in that there are more manuscripts of the New Testament than all other pre-1000 AD texts COMBINED, withe earliest manuscripts dating to within 25 years of the original.
In summary, Christianity hinges on the Resurrection of Jesus.