In the Bible, a once notorious murderer informs a first century church that certain people cannot enter the kingdom of heaven.  Everyone who read his words knew of his past.  How comforting must it have been when he informed them but this was no longer true.  (“Such as were some of you, but you were washed and sanctified.”)    Obviously, change has been around for thousands of years.  Why then is it so difficult for certain segments of society to deny human change.   A renowned psychologist explains this factor and his observations here: http://narth.com/2013/09/why-gays-cannot-speak-for-ex-gays/#more-3361