And he said unto him, If they hear not Moses and the prophets, neither will they be persuaded, though one rose from the dead. A correct hermeneutic will go a long way toward healing some of the division in the church. All division is not a result of sin. The Bible is not at fault. A correct hermeneutic will go a long way toward the questions of the unbelievers.
Some unbelief is a result of sinful lives.
Bad interpretation is the cause of some unbelief. The answer to bad interpretation is not no interpretation but a good interpretation. We get many different answers to this question, this discourages many from looking for themselves. But in every nation he that feareth him, and worketh righteousness, is accepted with him. A good translation or translations is the starting point.