And mark in every face I meet
Marks of weakness, marks of woe

As the speaker wanders through London, he notes that its people are “marked” with fatigue and distress. The suffering in London is nearly universal; he sees it in every face he passes on the street. It is important to note that there would have been some people—namely, aristocrats—who did not experience the degree of hardship that Blake describes in this poem. But the people the narrator meets face-to-face in the streets are those of the lower and middle classes, for whom “weakness” and “woe” were an everyday reality. 

In every cry of every man,
In every Infant’s cry of fear,
In every voice, in every ban,

Blake returns to the idea that every person he encounters is experiencing hardship in the second stanza, where he repeats the phrase “in every” four times in a row. He emphasizes again that suffering is widespread, as it is heard in “every voice.” Blake also mentions two groups that face specific suffering: married couples (as implied by the word “ban,” or marriage proclamation) and infants.  

But most, thro’ midnight streets I hear
How the youthful Harlot’s curse
Blasts the new-born Infant’s tear,
And blights with plagues the Marriage hearse.

In the poem’s final quatrain, the fact that the narrator sees the “Harlot’s curse” as the epitome of London’s evils is highlighted by the dark image of “midnight streets.” The venereal diseases contracted through prostitution passed into marriages and affected newborn children: innocent infants, then, instead of representing new life and joy, became poignant symbols of London’s afflictions. In the same way, Blake associates marriage, which is usually considered a blessing and a holy sacrament of the church, with death with his image of the “Marriage hearse.” The “Harlot’s curse” Blake describes here enters into and corrupts two of life’s closest relationships: that of a mother and her newborn child and that of a married couple.