His desire that we be "so completely one with Him" has a ring of urgency, a burning desire that we love Him as much as He loves us. When two people  love each other, that very love proves to everyone that they belong  together. Love proves that certain individuals in our lives are friends and  a lack of it proves that other people are merely acquaintances or even  enemies.

Love proves its power by melting icy hearts, giving assurance, changing personalities, instilling joy and promoting a feeling of well-being that nothing else accomplishes.  

Love proves that we care - care enough to sacrifice for the good of another.

Love needs to prove itself; it strains to give proof of its intensity and is ingenious in its way of providing that proof.

The proof that comes from true love is hidden and unnoticed by the one who possesses it. The reason for this is that the person who loves God deeply and continues to love Him is so busy loving, he is not aware of his witness - the witness is the fruit of a deep love, not the cause of that love.

Jesus changes us into a beautiful image of Himself through the Power of the Holy Spirit living in our hearts.