Strength is titled "Lust" in the Thoth deck. It's one of my favorite depictions of the card in the palpable rawness of energy, passion, and vibrance that emanates from Babalon astride the great Beast. It's interesting, the cultural associations with the term "lust," and what it means. Though at its core it signifies deep desire and longing, it has over time come to represent this impulse primarily in the context of human sexuality, and in particular female sexuality, something that has been stigmatized in many ways throughout time. Many attempts have been made (since the beginning of time, perhaps) to dampen, control, and subdue the sexuality of women, precisely because it is the source of great power. In so many ways, it is the womb of all of humanity.
Crowley/Harris; U.S. Games Systems
Babalon is a woman, a mother, a creatrix, who entirely owns who and what she is. She is not a whore, she is the source of all that we are, sculptor of the energetic depths of her counterpart, Chaos. She owns her sexual power (upon delving deep, deep down, it becomes clear that energy is energy is energy, and sexual energy is an aspect of divine energy - Lust is not only about sexual energy, but all energy, raw force, which includes sexual energy as a source of vibrant, spiritual power).
On the most mundane levels, Strength, Lust, is inner power, strength of character, confidence and self-understanding. It is primal ferocity, tempered by intellect and wisdom. It is compassion and love. It is the divine spark within us.
I absolutely love what Lon Milo Duquette wrote about this card in his book titled, Understanding Aleister Crowley's Thoth Tarot (Weiser Books, 2003):
The supreme spiritual message of this card may be summed up something like this: Eventually each of us will come to a level of consciousness so profoundly high that the only level higher is the universal consciousness of deity itself. Our dissolution into the infinite is the ultimate sacrifice, the ultimate marriage. Deity lusts for that moment when all her children will return to her. Someday, each one of us will also lust for that moment (pg. 127).