I had an interesting epiphany about this card.
Zayin is the Disposing Intelligence. It represents "discrimination". To dispose something is to set it aside. The sword is a symbol of this because it represents air, and can cut things into pieces which resonates with discernment.
This path connects 3<---->6
3 is the number of growth & expansion. It's also a saturnian number, which represents restriction, boundaries, etc. These two qualities are one and the same. When something is divided into many parts, that creates the illusion of expansion
6 is the number of reciprocation. 6 is the number that "interfaces" with all the other number in a harmonious way and applies their principals in perfection.
So for 6 to apply the principals of 3 (expansion, understanding, etc) it must use Zayin, which can expand and reduce the whole through the power of discernment.
I was thinking about Raphael, and I realized that the image of the lovers contains his image. You can't see his face, but I think that must be Raphael.
Reason I see this, is because the first two letters Resh & Peh demonstrate the same action of Zayin that I described.
Resh is the solar light from AIN SVP AVR. The Peh from the boundless light represents the power of speech, which separates and gives things form. So Raphael's formula contains the clue that the undifferentiated light is differentiated into manifestation through the principal of separation & disposition. This sounds an awful lot like the path of Zayin!
And interestingly enough, the Lovers by Paul Foster Case has a picture of Raphael behind the man & the woman, which supports this perspective!