From the principal service Gospel:

Jesus, knowing that the Father had given all things into his hands, and that he had come from God and was going to God, got up from the table, took off his outer robe, and tied a towel around himself. Then he poured water into a basin and began to wash the disciples’ feet and to wipe them with the towel that was tied around him.
(John’s Gospel, chapter 13, verses 3-5, NRSV)

This glass is a section of the east window in Soham parish church.