How is the tyger an expression of the mystery of God's creation?

In "The Tyger," poet William Blake poses numerous questions about the creation of the tiger. Three mysteries surface from these questions: the tiger's physical characteristics, the tiger's vicious temperament, and the juxtaposition of the violent tiger with the milder parts of God's creation.
The tiger's colorings and markings are remarkable, as suggested by "burning bright." The creature looks as if it has flames of fire painted on its coat. Additionally, its piercing eyes back up that image. The uniquely designed animal has a "fearful symmetry" in its powerful form. The poet questions what "immortal hand or eye" could be capable of producing such a marvelous being and imagines the creation took place in some "distant deeps or skies," someplace far removed from mortal workshops.
Beyond that, the tiger has a "heart" and "brain" that drive it to overpower and kill easily. Thus, it represents "deadly terrors" to any man or beast that should encounter it. Now the poet imagines a fiery forge that hammered out the vicious tendencies of the giant cat. He seems mystified by the possibly dark creative genius that could imagine and construct such unbridled aggression.
After contemplating the tiger's unique physical characteristics and its innate ferocity, the poet ponders how this creation fits in with other works of the same Creator. Here he seems utterly flummoxed. The very heavens, he supposes, wept at the invention that is so wildly uncharacteristic of the Creator's handiwork (for example, compared to the lamb). The cavernous divergence of the two species seems to present itself as the greatest of the three mysteries of creation that the poet considers.