Original sentence: Today, many advocate the addition of a 15th station depicting Christ's Resurrection, because without his rising from the dead he would not have accomplished the salvation that Christians believe was his mission – the same consideration that causes the three days commencing with the evening Mass of the Lord's Supper on  Holy Thursday and concluding with Vespers on the evening of Easter Sunday to be regarded as a liturgical unity, the so-called Holy Tridium, the Easter Tridium or Paschal Triduum
Edited sentence: Today, many advocate the addition of a 15th station depicting Christ's Resurrection, because without his rising from the dead he would not have accomplished the salvation that was his mission – the same consideration that causes the three days commencing with the evening Mass of the Lord's Supper on  Holy Thursday and concluding with Vespers on the evening of Easter Sunday to be regarded as a liturgical unity, the so-called Holy Tridium, the Easter Tridium or Paschal Triduum