An in-created morality

The revelation of man’s duty toward his Creator is part of the original “covenant of creation.”  Genesis only mentions explicitly the command to be fruitful, multiply, fill, and rule over the earth (Gen. 1:28ff).  But by its very nature, this command comprehends all of human life, and thus implies God’s moral order for human existence.  For man to be man means to be in relationship with God, and therefore under moral obligation to God.  We can’t properly understand human nature without reference to the moral law.  This idea of an in-created morality (as part of human nature itself) stands in direct antithesis to the humanist notion that man must create his own reality and morality — either individualistically (e.g., existentialism) or collectively (e.g., marxism).