A scourge is a whip or lash, especially a multi-thong type, used to inflict severe corporal punishment or self-mortification. It is usually made of leather.
Medical examination photo of Gordon showing his scourged back, widely distributed by Abolitionists to expose the brutality of slavery.
Reproduction of a medieval scourge
A discipline is a small scourge used as an instrument of penance by certain members of some Christian denominations in the spiritual discipline known as mortification of the flesh.
Scourge
…for excess of zeal, his example and the high esteem in which he was held did much to popularize the voluntary use of a small scourge known as a discipline, as a means of mortification and penance. From then on the practice appeared in most medieval religious orders and associations. The fourteenth-century…
A discipline with seven cords lying on top of the Raccolta, a Catholic prayer book containing several acts of reparation, and other devotions. Beside it are several sacramentals: a rosary, the Fivefold Scapular, a crucifix, and a phial of holy oil of Saint Philomena.
Fresco in the Basilica of Santa Maria Novella showing Saint Dominic with a discipline in his hand, kneeling before a crucifix
A confraternity of penitents in Italy mortifying the flesh with disciplines in a seven-hour procession; capirote are worn by penitents so that attention is not drawn towards themselves as they repent.