What is "The Haw Lantern" about?

Seamus Heaney uses the image of the haw to present ideas about light, in a physical sense, and about enlightenment. The speaker ruminates on the ways that guilt or innocence might be judged, as they (the speaker) wish to be cleared of the unstated charge leveled against them.
The haw is a viburnum, a plant that produces red berries similar to those of the holly; most viburnums are deciduous, while the holly is evergreen. The speaker contrasts the small amount of illumination that the haw’s berry can provide to the bold glow that a lantern would offer. Although this berry is not a lantern, it stands out against its darker surroundings and thus slightly illuminates the way of a person walking through the woods. The metaphorical aspect of providing light is compared to the lantern that Diogenes held; this ancient Greek became known for his constant quest to find an honest man. The speaker imagines Diogenes behind the bush, scrutinizing them, and wishes that the test that is applied would clear them. Whether the speaker is actually guilty of something or just feels guilty remains unstated; their uneasiness is implied by their flinching when the lantern shines on them.
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