Where in the bible does it say marriage is between a man and woman?
Is it said directly or does it involve metaphorical interpretation?
"But because there is so much sexual immorality, each man should have his own wife and each woman should have her own husband." [I Cor 7:2]
"But from the beginning of the creation God made them male and female. For this cause shall a man leave his father and mother, and cleave to his wife; And they twain shall be one flesh: so then they are no more twain, but one flesh. [Mark 10:6-8]
"If a man also lie with mankind, as he lieth with a woman, both of them have committed an abomination: they shall surely be put to death; their blood shall be upon them." [Leviticus 20:13]
Genesis 2, v's 23-25; Matthew 19, v's 4-6; Ephesians 5, v's 28-33 (and this is just for starters).
Adam and Eve