Assalaam Alaikum Wa Rahmatullahi Wa Barakatuh,

The intelligence is, for example, like a tool. If you do not sell it to Allah Almighty, but rather employ it for the sake of the soul, it will become an ill-omened, noxious and debilitating tool that will burden your weak person with all the sad sorrows of the past and the terrifying fears of the future; it will descend to the rank of an inauspicious and destructive tool. It is for this reason that a sinful man will frequently resort to drunkenness or frivolous pleasure in order to escape the vexations and injuries of his intelligence. But if you sell your intelligence to its True Owner and employ it on His behalf, then the intelligence will become like the key to a talisman, unlocking the infinite treasures of compassion and the vaults of wisdom that creation contains.
To take another example, the eye is one of the senses, a window through which the spirit looks out on this world. If you do not sell it to Allah Almighty, but rather employ it on behalf of the soul, by gazing upon a handful of transient, impermanent beauties and scenes, it will sink to the level of being a pander to lust and the concupiscent soul. But if you sell the eye to your All-Seeing Maker, and employ it on His behalf and within limits traced out by Him, then your eye will rise to the rank of a reader of the great book of being, a witness to the miracles of dominical art, a blessed bee sucking on the blossoms of mercy in the garden of this globe.
Yet another example is that of the tongue and the sense of taste. If you do not sell it to your Wise Creator, but employ it instead on behalf of the soul and for the sake of the stomach, it sinks and declines to the level of a gatekeeper at the stable of the stomach, a watchman at its factory. But if you sell it to the Generous Provider, the the sense of taste contained in the tongue will rise to the rank of a skilled overseer of the treasuries of Divine compassion, a grateful inspector in the kitchens of Allah’s eternal power.