A suggestion is a "hint", and thus indicates that the subtle or indirect method is the most effective because a suggestion bypasses our conscious defenses and goes straight into our subconscious mind which then elaborates upon the hint and generates resulting images, thoughts, emotions, feelings, etc.. .  

The positive use of suggestion is to "humanize" our drives, and the only way to tame our desires while still retaining their strength and vitality is through Loving discipline (which is neither asceticism, nor indulgence).  It is our self conscious attention to our various states of feeling, being, acting, and reacting, which is responsible for humanizing our subconscious.  Desire is sublimated through intelligent reflection and self examination motivated by Love, and by exercising loving self-discipline in our choices of what "foods" to put into our eyes, ears, minds, and stomachs.

Hebrew Name:    Teth (serpent)
The Hebrew letter for this aspect of consciousness is Teth, meaning "Snake, or Serpent", and the shape of the letter itself is in the shape of a coiled serpent.  The snake is symbolic of the force which is also known by the names "serpent power", "astral light", and "Fohat".  "It is the cosmic electricity, the universal life-principle which takes form as all things, and builds everything from within. [...] The serpent also symbolizes secrecy, subtlety, and wisdom."¹  As suggestions derived from faulty observations lead to illusion and delusion, the serpent-power is also known as the "father of lies".  "Yet when it is overcome, it becomes the instrumentality of salvation."²  That which leads us into temptation, eventually does deliver us from evil once we learn to control it.  The serpent and the redeemer are in fact the same.  

Attributed to Teth is the sense of Taste and Digestion.  As the serpent bites its own tail, so too "the serpent power feeds on itself [...] it is self sustaining."³  The Life Power manifests in "various forms of expression which feed upon one another." ⁴  Also, taste, digestion, and suggestion have much in common in that they all refer to (physical & mental) substances which are digested.

Qabalistic Intelligence:     The Intelligence of the Secret of all Spiritual Activities
Everything is Spirit.  Thus ALL activities are spiritual, no matter what the appearance.  One half of the secret is the fact that "all forces and activities whatsoever are transmutations and conversions of the one Conscious Energy."  The other half of the secret is that since ALL is spirit, the secret to success in any endeavor lies in engaging fully, but not having attachment or anxiety about the result.   

The secret is in knowing that victory lies in knowing how to make this apparent adversary (fear of failure, anxiety, dangerous lion, animal nature, force of nature, serpent power, powerful life force energy) an ally.  This is accomplished by realizing that "ends and means", "efforts and results",  are all ultimately the substance and activity of the One Life Power.  Thus, there is no failure.  Knowing this fact, courage and confident expectation become the primary suggestions which in fact do lead to a successful outcome, whatever the appearances may seem to be. ⁵

Astrological Correspondence:    Leo
The astrological symbol for Leo (b) resembles a serpent.  Attributes of Leo are:  enthusiasm, power, expansiveness, generosity, nobility, courage, fixed opinion, pride.  Leo is ruled by the Sun.

Number:    8
"Rhythm, alternate cycles of involution and evolution, vibration, flux and reflux, and the like. It represents also the fact that opposite forms of expression (that is, all pairs of opposites) are effects of a single Cause."⁶ 

Color / Note:    Yellow / E

Tarot Key:  Strength

Symbolism:  
(Summarized from "The Tarot", by P.F.Case)⁷ 

The Scene:    A woman lovingly caresses a powerful Lion, holding (open) his mouth.  

The Woman:    Represents subconsciousness (High Priestess, Eve, The Empress), creative imagination, and the subconscious generation of mental imagery. Dressed in white, she is motivated by purified desire, or Love. She directs the Lion, meaning that subconsciousness controls all forms of life below the human level. The lemniscate (figure 8) above her head links her to the Magician (K1), and intimates that subconsciousness is always amenable to control from the self consciousness.

The Lion:    The Animal Nature (the vital animal soul), both within us, and in nature. The fiery Kundalini energy.  This aspect always expresses under the direct control of the woman (subconsciousness) whether it appear wild and untamed, sick and lamed, or full of vitality, nobility, and spirit.  You can also think of the Lion as an untamed aspect of your personality you are expressing or working on mastering, such as anger, lust, or an addiction. (note: in the esoteric B.O.T.A. tarot key, this lion is drawn in the color Red).

The Chain of Roses:    The woman and Lion are linked by a chain of roses, symbolizing desire. We cultivate desire through the rose of Venus, through the drives of love.

In "Living the Tarot", Amber Jayanti provides some suggestions for integration and application of Strength:

Illustrations from the Universal Waite Tarot Deck reproduced by permission of U.S. Games Systems, Inc., Stamford, CT 06902 USA. Copyright ©1990 by U.S. Games Systems, Inc. Further reproduction prohibited.