Marriage has been established by the Creator; it is therefore not a humanly devised institution. It existed from the beginning, as Jesus himself defined the origin and essence of marriage.

Genesis 2:20-24
And Adam gave names to all cattle, and to the fowl of the air, and to every beast of the field; but for Adam there was not found an help meet for him.

Genesis 2:24
Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.

2 Corinthians 6:14
Be ye not unequally yoked together with unbelievers: for what fellowship hath righteousness with unrighteousness? and what communion hath light with darkness?

Ephesians 5:25-33
Husbands, love your wives, even as Christ also loved the church, and gave himself for it;

1 Corinthians 7:1-40
Now concerning the things whereof ye wrote unto me: [It is] good for a man not to touch a woman.