So Christ is our life. Eternal life is not some heavenly substance that God imparts when we trust our Savior. Eternal life is Jesus Christ Himself.
Already, as members of God's church, we are tied completely to Christ's life. And that will increase in many ways as we receive the many blessings that will be coming.
We are dead and alive at the same time, dead to sin and alive in Christ. Someone once said, Life is what you are alive to. A child may come alive when you talk about ice cream. The teenager may come alive when you mention cars in that physical sense.
So Christ was Paul's life and he was dedicated to everything related to Christ. Likewise, every member of God's church should behave that way toward the Groom.
Now He is our life, which is another way of saying that we are sharers of His life. When Paul wrote in Ephesians 5:30, We are members of His body, of His flesh and of His bones, it expresses the same idea. So we are now viewing it from a slightly different angle and not so much from the perspective of spiritual union but through Christ's own consciousness, so to speak.
He is giving His life, sharing it, and we are brought into it, becoming an intimate part of His life. This is the part that we are in, the sanctification, where Jesus trains us and shapes us into what a bride should be for Him.