"... The reasoning goes, "God is perfect, therefore what God said to people in the past is the epitome of perfection. The original Christians, being close in time to Christ and the Apostles, must have had the more perfect knowledge. So the best that we can ever do is to swear allegiance to the original words and emulate the original Christians in action."
This line of thinking leaves out something very important. While God doesn't change, and basic human nature doesn't change, some things do change. Civilization does change in its ability to be a benchmark of moral behavior. Civilization changes in its ability to understand the ins and outs of moral behavior. Civilization changes in its needs, with government, education, and science minimizing needs." (link below)
I would add to that so does religion because it is part of civilization. Religion follows along with society, sometimes ahead sometimes behind. We are a tolerant nation and people (some are) that no longer kills heretics for beliefs that once seemed so real. So in a real sense religion has changed greatly and continues to do so as the Episcopalians proved not long ago. Consider the changes concerning the following.
Role of women
Gays
Judging others OT NT
Murder
Sabbath Day
Divorce
Money / riches
Witches / devils / crusades
Or consider the church's attitude towards children. "If the Church continues singing the same song, "be fruitful and multiply," with no responsible concern for population control, then we are on a collision course with reality. It is up to the Church to provide us with sound moral advice that works for today's world - or stand aside and become insignificant." This has changed greatly in our lifetime and except for orthodox religious hardly gets notice.
"Are the Scriptures books of pat answers, or do they tell experiences that help us consider various responses to problems in a caring setting. The fact that we do change is illustrated in our looking back at things in the Bible and finding them immoral. Today such things as slavery, taking multiple wives, stoning to death misbehaving children and other minor offenders (prostitutes), and divorcing over failure to produce children, are recognized as harmful actions and are not tolerated or are banned. Society and people grow in understanding, and their needs change, but the past can't change, nor can the past get better informed or any smarter than it was."
quotes from
http://www.visualwriter.com/HumanCond/Morality.htm