How does Milton resolve that problem in the sestet?

In the sestet of "On His Blindness," Milton resolves his struggle with loss and his purpose by acknowledging that serving God does not solely depend on one's physical abilities. He realizes that faith and devotion can manifest in various ways, and that even in blindness, he can fulfill his divine purpose. The poem concludes with the understanding that God's expectations are not limited to active service; patience and acceptance of one's circumstances are also valuable in the eyes of the divine.