Copyrighting
It ensures that no one can copy their work and try to claim it as their own
A belief that the strongest or fittest should survive and flourish in society while the weak and unfit should be allowed to die
Okay so I'm going to answer this, but first I have to disclose that I went to a Christian school. I don't think that matters much so here I go.
You asking "Why" the Christians borrowed some of the ways of worship form the Jewish religion; but first, what did they borrow? I will first point out that both Christianity and Judaism are Abrahamic religions, which basically just states that they both believe a man named Abraham roamed the earth at one point. The reason behind believing this is that Abraham worshiped a divine power. Once you divulge into the divine power, the ideals in these religions divide, but the point is that they both believe in a divine power.
Then one might say the act of worshiping anything is something christianity borrowed from the Jewish culture, and that is not false.