There is a difference between "ethics" and "morals." Ethics do not change. Morals reflect the changing whims of culture. For the Christian, ethics must be rooted in the absolutes revealed in God's Word to inform and nurture our moral conduct. In the postmodern era, Christians must learn to think biblically and identify how we relate to culture.

Textbooks:

Christianity, Cults, Religion

Soteriology, the doctrine of salvation, is one of the grandest themes in the Scriptures. It embraces all of time as well as eternity past and future.  It relates in one way or and New Testaments.  It is personal, national, and cosmic.  And it centers on the greatest Person, our Lord Jesus Christ.