This is "A Young Woman kneeling at a Prayer Desk" painted in 1813 by Sir David Wilkie. The painting shows a young girl, believed to be Lady Augusta Phipps, the 12-year-old daughter of the 1st Earl Mulgrave, kneeling before an altar on which two tall candles have been lit.
Her hands are placed in prayer on a large open Bible and above the prayer table is a small altarpiece with an inscription in Gothic script from the Lord's Prayer. The girl turns to look at us as if interrupted during her devotions, giving the portrait a sense of poignancy.
The painting is remarkably rich in colour and deft in its painterly technique, reminiscent of an old master. The artist has captured the face of a young girl poised between childhood and adulthood with great accuracy and delicacy.
It's worth noting that this painting was painted just a year before Lady Augusta died, which adds to its poignancy. It may have been intended as a memorial to her.
A Young Woman kneeling at a Prayer Desk hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.