So fine and subtle as to be imperceptible to human sight; so pure as to be imperceptible.
“That is Allah, your Lord! There is no god but He, the Creator of all things; then worship ye Him; and He hath power to dispose of all affairs. No vision can grasp Him. But His grasp is over all vision: HE IS ABOVE ALL COMPREHENSION, yet is acquainted with all things. “How have come to you, from your Lord, proofs (to open your eyes): if any will see, it will be for (the good of) his own soul; if any will be blind, it will be to his own (harm): I am not (here) to watch over your do- ings.”
(6:102…104) The Holy Quran

From the root l-t-f with the classical Arabic connotations: to be delicate, refined, elegant, graceful to be gentle, gracious, courteous, kindly to be subtle, to know the obscurities of all affairs to treat with regard for circumstances
Allah is most subtle and gracious. His nature is gentle, affectionate, courteous and refined.
He is kind, gracious, and understanding, with regard for the subtle details of individual circumstances.
His actions are so fine and subtle that they may be imperceptible, beyond our comprehension.
His delicate perception reveals the subtleties of all things.
