Please discuss "The Tyger" by William Blake.

In "The Tyger," Blake takes time to ruminate on what kind of God could make a creature as fearsome as a tiger. In doing so, he employs an eighteenth-century concept known as "the sublime." The sublime refers to those aspects of nature that both fill us with awe at their beauty but also with terror at their power. Standing at the edge of a tall mountain peak and seeing both the majesty of the mountain while recognizing the smallness and weakness of humans in comparison to the God who could create such grandeur would be an example of the sublime.
Blake describes the tiger in terms of the sublime: it is both beautiful and terrifying. As Blake asks:

What immortal hand or eye,
Dare frame thy fearful symmetry?

Behind this question lurks another: what kind of God could unleash such destructive power on the earth? The tiger is beautiful, but its "symmetry" is used to pounce on the victims it will devour. Blake explicitly contrasts it to the lamb, asking "Did he who made the Lamb make thee?"

If we completely understood the God we think we know, we would understand why a God who we are often taught is like a lamb, a creature of gentleness, mercy, and sacrifice, also unleashes aggressive and destructive forces on the earth. Blake asks if God smiled as he created the tiger. Does God like power, aggression, and destruction as well as love, peace, and joy? Blake's poem, in my opinion, inspires us to ponder the mystery of a Christian God who is both a God of love and mercy and one of aggressive power and wrath. The world is a complicated creation, and God evades the platitudes we often repeat to try to define him. Blake's evocations of God as a gentle lamb is only half the picture, and it is the other half, symbolized by the predatory tiger, that troubles us.

William Blake's "The Tyger" is a profound and subtly disturbing work that, at its essence, seeks to understand the nature of God and whether or not He is responsible for creating the destructive forces represented by the tiger.
The key lines here are as follows:

What immortal hand or eye, 
Could frame thy fearful symmetry? (3-4)

These lines appear twice, once at the end of the first stanza, and then again at the end of the poem. On the surface level, Blake is asking what kind of power (be it the traditional God or something else entirely) made the tiger. On another, more abstract, interpretive level, Blake is wondering what is responsible for the "fearful symmetry" of the world. Throughout the poem, Blake grapples with this "fearful symmetry," referencing chaotic events such as the fall of the angels following Satan's failed rebellion (alluded to in the fifth stanza by "When the stars threw down their spears / And water'd heaven with their tears" (17-18)). As such, though Blake is ostensibly discussing a tiger, he's also struggling to come to terms with the concept of God, and he questions whether God is responsible for the destructive, chaotic events of the world. This question is never resolved, and the final ambiguity of the poem (which returns once more to the ominous "fearful symmetry") leaves the reader with a brilliantly subtle sense of unease. 
https://www.poetryfoundation.org/poems/43687/the-tyger

“The Tyger” by William Blake was published in his book Songs of Innocence and of Experience  in 1794. The poem is 24 lines long, divided into six quatrains. It is written in iambic tetrameter. The quatrains each consist of two couplets, meaning that they rhyme AABB. The first and sixth quatrains are identical. 
The poem is written in the voice of a narrator who addresses the "Tyger" in the second person. One unusual aspect of the poem is that is consists mainly of a series of questions addressed to the Tyger rather than declarative statements. 
The poem uses a significant amount of religious symbolism, synthesizing traditional Christian iconography with Blake's own idiosyncratic belief system. The narrator seems to be querying the Tyger in part to understand the nature of the Creator, wondering what sort of Creator could account for the Tyger's beauty, majesty, and ferocity. The narrator also struggles to understand how a single Creator could have made something as fierce as the Tyger and as gentle as the Lamb.