"Design" is a sonnet by Robert Frost that like many of Frost's works reflects on simple, natural phenomena in a way that illuminates profound philosophical and human issues. The surface level of the poem is deceptively simple. It describes a spider sitting on a flower consuming a moth. The spiritual questions stem from the poet wondering not what is happening in the scene but why, as set forth in the lines:
What brought the kindred spider to that height,
Then steered the white moth thither in the night?
What complicates this image is the question of "design". The spider's life depends on the death of the moth. In a Darwinian universe, the "design" of the poem is the way nature operates to ensure the survival of the fittest, with the strong preying on the weak in a constant struggle for survival.
From a religious or moral point of view, this might appear unfair or even evil. The white moth set against the white flower appears innocent and does not in any way merit a slow painful death, trapped in a web and then eaten by a spider. Thus the poem makes us reflect on how the design of divine providence appears to care little for the individual.
The spider itself though raises another question in the minds of educated readers. Among the most famous sermons (and one growing out of New England, the region in which Frost lived and in which his poems are set) is "Sinners in the Hands of an Angry God" by Jonathan Edwards which compares humans to disgusting spiders dangled over a burning pit by a thin thread. This parallel suggests that all life is precarious and that the design which leads to the death of the moth at the hands of a spider will spare neither spiders nor humans in the end.
Finally, the speculation "If design govern in a thing so small" plays on the statement in Matthew 10:29 that "Yet not a single sparrow falls to the ground without your Father's [God's] knowledge" which suggests that God's design does, in fact, govern the smallest of creatures and thus that we must look at the moth and spider as part of that design rather than as a random event.