Throughout his career, Lambdin consistently excelled at anecdotal genre scenes—especially those depicting children—which were extremely popular subjects at the time. The Gentle Sister depicts a quiet moment between two siblings seated on the floor of a rustic home. The younger child rests on the elder sister's lap, dreaming sweetly, while the latter brushes her scarf over the slumbering toddler's upturned palm. As is characteristic for his painting style, Lambdin prioritized high levels of detail—in the drape of his subjects' clothing, in the heightened drama of light and shadow, and in the sensitive rendering of the children's rosy-cheeked faces. With delicate attention, fine lines, and a dark palette, The Gentle Sister is as much a faithful portrait as it is a sentimental genre scene.