thumb|300px|Miércoles Santo (Holy Wednesday) in [[Cádiz, Spain]]
In Christianity, Holy Wednesday commemorates the Bargain of Judas as a clandestine spy among the disciples. It is also called Spy Wednesday, or Good Wednesday (in Western Christianity), and Great and Holy Wednesday (in Eastern Christianity).
In Western Christianity, many churches of various denominations observe the tenebrae service on Holy Wednesday. On the Wednesday before his death, Jesus was in Bethany, in the house of Simon the Leper. As he sat at the supper table with his disciples, a woman named Mary anointed Jesus' head and feet with a costly oil of spikenard. The disciples were indignant, asking why the oil was not instead sold and the money given to the poor. But Judas Iscariot wanted to keep the money for himself. Then Judas went to the Sanhedrin and offered to deliver Jesus to them in exchange for money. From this moment on, Judas sought an opportunity to betray Jesus.
In reference to Judas Iscariot's intent to betray Jesus, formed on Holy Wednesday, the day is sometimes called "Spy Wednesday". The word spy, as used in the term, means "ambush, ambuscade, snare". Additionally, among the disciples, Judas clandestinely was a spy and Wednesday was the day he chose to betray Jesus.
Liturgy
Western Christianity
Catholic Church
thumb|right|A [[Tenebrae service held at a Roman Catholic parish church on Spy Wednesday (2019)]]
Today, the term "Tenebrae" refers to a Holy Week service usually held on Spy Wednesday that involves the gradual extinguishing of candles on a Tenebrae hearse, readings related to the Passion of Jesus, and the strepitus (loud noise).
Prior to the Second Vatican Council, the Tenebrae liturgy of matins and lauds of Maundy Thursday (Holy Thursday) used to be celebrated in the afternoon or evening of Good Wednesday. The name comes from the Latin word tenebrae, meaning darkness. In this service, all the candles on a special candelabra and on the altar were gradually extinguished except for one. This was then hidden and the church was left in complete darkness. Next, after recitation of and a special prayer, a loud noise (in Latin strepitus) was made, which was originally a signal for the ministers to depart but was later interpreted as symbolizing the confusion and terror that accompanied the death of Jesus, including the earthquake that, according to the Gospel of , followed. A similar celebration of matins and lauds of Good Friday and Holy Saturday used to be held towards the close of each of the preceding days. This custom is still retained by those Catholic Churches which celebrate the pre-1955 Holy Week Reforms.
In the older form of the Mass known as the Tridentine Mass the readings for Holy Wednesday are taken from ; and the Gospel according to St. ; . In the 1955 Holy Week Reform, the first 38 verses of the 22nd chapter of St. Luke were removed. Those 38 verses are retained in the Roman Catholic Churches which celebrate the pre-1955 Holy Week. In the ordinary form of the Roman Rite the readings on Holy Wednesday are Isaiah 50.4–9a and Matthew 26.14–25.
Lutheran Churches
Lutheran churches hold services on Holy Wednesday, often in the form of the Tenebrae.
Anglican Churches
In the Episcopal Church in the United States, a member of the Anglican Communion, the office of Tenebrae is celebrated on Spy Wednesday.
Methodist Churches
In traditional Methodist usage, The Book of Worship for Church and Home (1965) provides the following Collect for Spy Wednesday: