There is no need for confusion at all.

It is showing very clearly that there is lot of common things between bible and islam.so we have to ask and find answeres for following questions.

1.why there is common things in both books?
2.if bible is beleived to say it has similar teachings as quran, then why quran came after that.?
3.whats the purpose of God creating jesus and mohammed?
4.If the God of Jesus and Mohammed is one, then for whom is bible and Quran intended?