Marriage is an amazing thing. That two strangers with completely different backgrounds, personalities and goals can come together, become one, share everything, raise mini versions of themselves and live together in (mostly) complete harmony is a miracle.

After the creation of everything else in the universe, God created Adam and provided living accommodation, food and an abundant supply of pets. Even with all of this the Lord found that Adam was still lonely (Genesis 2:18). He took a rib from Adam, fashioned Eve from it (Genesis 2:21-22) and presented her to Adam, who promptly exclaimed “Wo! Man” and thus were half of the human race labeled. This God ordained relationship was the first marriage and sets the pattern that we would do well to follow (other than guys rightly being cautious of unexpected offers of fruit from their wives).

The scriptures offer no explanation of why God chose to fashion Eve from one of Adam's ribs. Upon careful reading and contemplation there appear to be two possibilities, but as one of them is a very bad joke with the punchline of "What can I get for a rib?", I'll skip over it and go to my preferred sensible answer.

I believe that God used a rib because he firstly wanted Eve to be of the same substance of Adam. Everything else in the universe was spoken into existence during creation, but Adam was specifically hand made by God from the dust of the ground and provided life by the breath of God (Genesis 2:7). This alone made him unique in the universe and a compatible mate would need to be similarly constituted. Secondly, a rib is from the side of the body. Eve was neither intended to be above nor below Adam, but to be his help meet who would be by his side all of their lives. And finally, a rib's purpose in life is to protect the most vital organs of the body: the lungs and especially the heart. Adam's rib shows that Eve was under his protection and that she was a vital part of his being that he would defend with his life.