The poem
"I die, I die!" the Mother said, "My children die for lack of bread. What more has the merciless Tyrant said?" The Monk sat down on the stony bed.
The blood red ran from the Grey Monk's side, His hands and feet were wounded wide, His body bent, his arms and knees Like to the roots of ancient trees.
His eye was dry; no tear could flow: A hollow groan first spoke his woe. He trembled and shudder'd upon the bed; At length with a feeble cry he said:
"When God commanded this hand to write In the studious hours of deep midnight, He told me the writing I wrote should prove The bane of all that on Earth I lov'd.
My Brother starv'd between two walls, His Children's cry my soul appalls; I mock'd at the rack and griding chain, My bent body mocks their torturing pain.
Thy father drew his sword in the North, With his thousands strong he marched forth; Thy Brother has arm'd himself in steel To avenge the wrongs thy Children feel.
But vain the Sword and vain the Bow, They never can work War's overthrow. The Hermit's prayer and the Widow's tear Alone can free the World from fear.
For a Tear is an intellectual thing, And a Sigh is the sword of an Angel King, And the bitter groan of the Martyr's woe Is an arrow from the Almighty's bow.
The hand of Vengeance found the bed To which the Purple Tyrant fled; The iron hand crush'd the Tyrant's head And became a Tyrant in his stead."

How does the mother encounter the Monk? Did she actively seek him? Bump into him? She valued his opinion and trusted him enough to state the condition of herself and her children: "I die...my children lack bread..." These are the only brief words of the woman, and yet, I infer that she is a widow ("The Widow's tear", line 27). The monk is old; he is versed in the political condition of his time, and he arrives at…
Read the whole commentHow does the mother encounter the Monk? Did she actively seek him? Bump into him? She valued his opinion and trusted him enough to state the condition of herself and her children: "I die...my children lack bread..." These are the only brief words of the woman, and yet, I infer that she is a widow ("The Widow's tear", line 27). The monk is old; he is versed in the political condition of his time, and he arrives at the conclusion that the Tyrant is a series of Tyrants. The monk has suffered personal loss. The brother I take to be either a blood relative, or a brother of the cloth. Scores have suffered, and will continue to suffer because "the sword and vain the bow/they never can work War's overthrow." Man's efforts to end strife never succeed because peace merely breeds another form of a tyrant. The monk's writings, which God commanded him to write, are painful because the truth, to the monk, is that misery is a given state of the earth. The monk loves his people and the Earth enough to do the religious practice of inflicting the whip upon himself, and further bearing the marks of Christ upon his own body ("blood red ran from the Grey Monk's side, His hands & feet were wounded wide"). He believes in daily prayers (stanza 2), nightly meditations (stanza 4)and the ultimate "victory" of intercession (stanza 7).
Blake uses well-crafted language throughout this poem. Scientists, philosophers,writers, artists and entertainers love "lifting" quotes, such as, "For a tear is an intellectual thing" to cite just one.
To me, this is a poem of resignation of the natural state of man and the ultimate need for God to save mankind from itself. The powers that be lack the true conviction to rule honestly. Corruption is the result of man's fallen state.
Throughout the poem, the monk's tone (hollow groan,feeble cry), actions (physical weakness, overall resignation, matter-of-fact accounting of sufferings that have taken place that he has witnessed and experienced)and conclusion(a tyrant in his stead)seem to be one not of bleakness, but of merely accounting. Even the monk's grey color, literally and figuratively, allude to a condition or a telling.
I disagree that the outlook of the poem is pessimistic about man's ability to end tyranny on his own. Rather it admonishes the indignant person to counteract tyranny by refusing to participate in its workings either violently in opposition or complacently in support of a given tyrannical system, as such types of participation serve as the basis for all tyranny.