William Blake was an artist and a poet. These two professions were strongly intertwined. In his works, he presents his thoughts through poetry and enhances the pictures they inspire; it's almost as if he completes the thoughts included in his rhymes with his drawings, which are symbols that represent ideas. 

The major themes of Blake's Poems :

Nature :

Nature, according to Blake, is a symbol for human fall. To him, being in Nature means being cut off from the world of imagination, the world that, through extraordinary and illuminating visions, brings humans closer to knowledge and consciousness of their own existence. And, while he considered Nature to be a part of the earthly world, he recognized her beauty and harmony, and believed that it is through Nature that man might come to understand their place in the universe, in the Creation.

Innocence and Experience :

Blake was continually examining the moment of lost childhood, similar to his attention on man's fall from grace. This repeating topic in Blake's poetry works almost as a model for all of the other themes described thus far. The notion of opposition, cycling, repression, and sexuality is highlighted by the theme of separation, transition, and contrast between innocence and experience. With the exception of Songs of Innocence and Experience , Blake continues to personify and explore this brief moment and its results.

Opposition :

"Opposition is true friendship," Blake wrote in "Marriage of Heaven and Hell." Even the poem's title alludes to his conception of a "marriage" of opposites. So much of Blake's work is based on the idea that in this world, antagonism symbolizes balance, and that focusing on one side over the other leads to injustice and ignorance. Many scholars claim that Blake was an extreme radical who sought to demolish any type of order that existed at the period.