The perfect time to start working on this ideal of a focused mind is before the time of Gemini in Taurus. 
The Hierophant is for marriage, particularly of the sephirot of Mercy to that of Wisdom. 
Together these are to forgo escaping with mental fantasy. 
The horse language is the hidden meaning of the Greek myth, named after Pegasus, which was the embodiment of the poet’s language. 
This realm of fantastic meaning needs to be steered by action. 
This is the horse of meaning we steer with ‘Reins’; as God steers the heart. 
For the archetype, we will go for the angel ORGANL. 

ORGANL rectifies in the spirit what is lost in the flesh. He follows RZL path of grief for ecstasy. By hard work, by toil, by doing what you would wish not, first: you leave only ecstasy in your path. 
The point of reins is that a focused mind reaches ecstatic heights; like I do in my dreams. The focus alone does it, as Huxley pointed out in The Doors of Perception: Heaven and Hell, put a brain wave graph on a meditating Buddhist and you will see those flatlining waves spike into epiphany. We live in a world of balance. 
Or as they say in mechanics: there is no free lunch. Adjust gas, spark or air: and the others must be adjusted to compensate. 
That air we are adjusting is the alchemical air symbolic of the mind. 
Compress the air into the piston chamber and.. we have a word for that: turbo. Focused air/mind turbocharges your consciousness. 
And the reins are symbolically that ability to wield that Greek Cabalic horse of meaning. Ride it or be trampled; the difference rests in your focused control to pursue meaningful endeavors. 
The link to the mahor arcana path connected with this minor arcana in the SbW in found by clicking here.
​The first set of paths to the HGA continues below with Furnace of Secrets: 

37.  🜁♘Furnace of Secrets; Focus; 🔥. Tipheret. God Point on MRKBH. Our gnome puts his hermetic egg into the decorative Furnace of Secrets. He will pull down the main door, just above our line of sight, and the egg will cook for months under his consistent supervision. Athanor comes from the Greek athanatos which means undying. An adept is he who is upon the Great Work; and the master tutors the adept. The master happens to be the athanor. Days one fifty nine through one sixty two flesh out a nine month grand work to reflect the hermetic egg in the athanor, that reflects your bushido. You’ll go through these steps in a new way, an additional day each, after finishing while completing this Great Work.

A gnome readies a rare amalgam to be forged into a hermetic sundial, which reveals different wisdoms with the passing of the shadows of time.