On Gen 2.24, Apostle Paul commented that ‘the mystery is profound, and I am saying that it refers to Christ and the church.’ Indeed, Christ left his father and hold fast to his wife, i.e., the church. And the two indeed become one flesh. I am thinking of two meanings. First, it could about the Word who became flesh, who took upon human form and thereby united himself with humankind. Second, more specifically, it’s about Christ being the head of the body which is the church.
When a man left his father and mother and hold fast to his wife and became one flesh, indeed its a great mystery. Hard to fathom, almost incomprehensible. It’s like when Christ left his father and came to the world. Only explainable by love.