The greatest old master painting in the Museum, Rogier van der Weyden's diptych presents the Crucifixion as a timeless dramatic narrative. To convey overwhelming depths of human emotion, Rogier located monumental forms in a shallow, austere, nocturnal space accented only by brilliant red hangings. He focused on the experience of the Virgin, her unbearable grief expressed by her swooning into the arms of John the Evangelist. The intensity of her anguish is echoed in the agitated, fluttering loincloth that moves around Christ's motionless body as if the air itself were astir with sorrow. Rogier's use of two panels in a diptych, rather than the more usual three found in a triptych, is rare in paintings of this period, and allowed the artist to balance the human despair at the darkest hour of the Christian faith against the promise of redemption.
Katherine Crawford Luber, from Philadelphia Museum of Art: Handbook of the Collections (1995), p. 167.