Christ the Eternal High Priest.
"The Feast of Our Lord Jesus Christ, the Eternal High Priest, according to the order of Melchizedek. In him the Father has been well pleased from before all time. As Mediator between God and human beings, fulfilling his Father’s will, he sacrificed himself once on the altar of the Cross as a saving Victim for the whole world. Thus, instituting the pattern of an everlasting sacrifice, with a brother’s kindness he chose, from among the children of Adam, men to augment the priesthood, so that, from the sacrifice continually renewed in the Church, streams of divine power might flow, whereby a new heaven and a new earth might be made, and throughout the whole universe there would be perfected what no eye has seen, nor ear heard, nor has entered into the human heart. The feast is Proper to England and Wales" on the Thursday after Pentecost. Stained glass window from St Patrick's Seminary in Menlo Park, CA.
Source: Lawrence OP on Flickr