The speaker begins in a tense, familiar situation: standing in a hot street with soldiers aiming rifles at him. Their mirrored sunglasses show him only his own small, thin reflection, and the soldiers become faceless, easy to hate. The poem suggests this is a routine humiliation, something he has endured "God knows how many times."
Then an explosion changes everything. Running to look, he finds a wounded soldier, one of the men he had resented, and feels shame for his earlier thoughts. The soldier's sunglasses are gone, and his bare eyes are "a clear, pale blue." Seeing them, the speaker stops seeing a symbol of threat and sees a vulnerable person, perhaps a very young one given the "smooth cheeks."
The mood moves from wary resentment to tenderness. The final lines, spoken as comfort, share the sky between them: "here is our sky, soldier, here is yours." The speaker offers care instead of hostility.