Primary metaphor
The mem מ, consiting of a kaf כ and a zayin ז joined at the top represents the joining of the son and his bride in heaven. Remembering the rule that says that the hidden things are revealed by the visible, or that the doctrine of the hidden must agree with that of the rest of scripture, it cannot speak of a marriage in heaven. Therefore it speaks of the Father-in-heaven's declaration that his Son would be married. He chose the bride.