This is actually a good question Fisherman!
Morality is about having principles to uphold the
distinction between right and wrong, where wrong inadvertently has negative
consequences on ourselves and/or other living being. As humanity gains a better
understanding of its environment and the consequences of its actions, morality
changes accordingly.
Though many would say that it is God that defines
morality, they must, nevertheless, admit that morality has changed since the
bible was written. For instance, having many wives, owning concubines and slaves
was accepted even by God’s people at one point. Should your wife cheat on you,
or simply tell you that she did not believe in your God, then, the moral thing
to do was to bring her out and stone her to death! However, overtime, these
religions have found various reasons not to uphold such beliefs, finding that
such behavior would conflict with modern morality.
Hence, it is not religion (God) that dictates morality,
but human society itself. Religion will than adapt their message by adjusting their
understanding of the will of God.