The union between man and woman, which we currently understand as the covenant of marriage, was part of God's original plan for His creation according to Genesis 2:
20 The man gave names to all livestock and to the birds of the heavens and to every beast of the field. But for Adam there was not found a helper fit for him. 21 So the Lord God caused a deep sleep to fall upon the man, and while he slept took one of his ribs and closed up its place with flesh. 22 And the rib that the Lord God had taken from the man he made into a woman and brought her to the man. 23 Then the man said,
“This at last is bone of my bones
and flesh of my flesh;
she shall be called Woman,
because she was taken out of Man.”
24 Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh.
[Genesis 2:20-24, ESV]
Notice that this was established before the fall, when sin had not yet infiltrated mankind. At this point, there was still no need for a Messiah and a plan of redemption. Yet, we are later revealed that marriage has a very important symbolic meaning: it points to the heavenly marriage between Jesus Christ (the Bridegroom) and the Church (his Bride):
6 Then I heard what seemed to be the voice of a great multitude, like the roar of many waters and like the sound of mighty peals of thunder, crying out,
“Hallelujah! For the Lord our God
the Almighty reigns. 7 Let us rejoice and exult
and give him the glory, for the marriage of the Lamb has come,
and his Bride has made herself ready; 8 it was granted her to clothe herself
with fine linen, bright and pure”—
for the fine linen is the righteous deeds of the saints.
9 And the angel said to me, “Write this: Blessed are those who are invited to the marriage supper of the Lamb.” And he said to me, “These are the true words of God.”
[Revelation 19:6-9, ESV]
This symbolic parallelism is in fact acknowledged as a mystery by Paul:
22 Wives, submit to your own husbands, as to the Lord. 23 For the husband is the head of the wife even as Christ is the head of the church, his body, and is himself its Savior. 24 Now as the church submits to Christ, so also wives should submit in everything to their husbands.
25 Husbands, love your wives, as Christ loved the church and gave himself up for her, 26 that he might sanctify her, having cleansed her by the washing of water with the word, 27 so that he might present the church to himself in splendor, without spot or wrinkle or any such thing, that she might be holy and without blemish. 28 In the same way husbands should love their wives as their own bodies. He who loves his wife loves himself. 29 For no one ever hated his own flesh, but nourishes and cherishes it, just as Christ does the church, 30 because we are members of his body. 31 “Therefore a man shall leave his father and mother and hold fast to his wife, and the two shall become one flesh.” 32 This mystery is profound, and I am saying that it refers to Christ and the church. 33 However, let each one of you love his wife as himself, and let the wife see that she respects her husband.
[Ephesians 5:22-33, ESV]
Question: Did God create marriage in Eden with a messianic symbolism already built in? Did God create Adam and Eve already knowing that they would fall and that there would be a need for a Savior, and a Church, and heavenly marriage between the two? In other words, was the fall of man always part of the plan, and was marriage created precisely to foreshadow the plan of redemption?