Intercession of saints
Intercession of the saints is a Christian doctrine common to the Catholic and Orthodox Churches. Intercessory prayer is a petition made to God on behalf of others. If a believer prays for his children or friends, his enemies or leaders, then the believer is interceding on behalf of another. The doctrine of saintly intercession goes back to the earliest church. The justification for calling upon a saint in prayer is that the saints are both close to God, because of their holiness, and accessible to humans.
Some christians say that Jesus' parable of Dives and Lazarus in Luke 16:19-31 indicates the ability of the dead to pray for the living. Paul's repeated references to Jesus Christ as "advocate" for the believers also may indicates that Jesus, living at the right hand of God, may intercede for the believer (Rom 8:34; Heb 7:25). By extension, other holy persons who are living in Christ on earth or in heaven(having left their earthly existence) may be able to intercede-through Christ- on behalf of the petitioner. (John 11:25; Rom 8:38-39) This is a controversial doctrine, because in some faiths, only Jesus is holy enough to intercede for people. From the Catholic and Orthodox Churches perspective: if those living here on earth can intercede in behalf of each other, then those which have already been glorified in heaven, and are even closer "in Christ", are made holy as "one" unified through him (the mediator between God and men- on earth and heaven) by his sacrifice, can certainly intercede for those on earth as well. (Heb 2:11, 10:10; 1 Tim 2:1-5)
Catholic Church doctrine supports intercessory prayer to saints. Intercesory prayer to saints also plays an important spot in the Eastern Orthodox and Oriental Orthodox churches. Also some Anglo-Catholics believe in saintly intercession. They may point to such Scriptural passages as Tobit 12:12,15, Revelation 5:8, or Revelation 8:3-4, which depict heavenly beings offering the prayers of mortals before God. As well as James 5:16, (where all those in heaven can be presumed to be living righteously) which states the prayer of the righteous is powerful and effective.
Protestant views
Many Protestant churches strongly reject all saintly intercession, in seeming accordance with verses like 1 Timothy 2:5, which says that Jesus is the only intercessor between God and man. The practice was attacked both by the Waldensians of the 12th century, and the various Gnostic Bogomil groups (including the Albigensians). The Calvinists and Zwinglians were particularly zealous in their rejection of saintly intercession. In the Church of England's Thirty-Nine Articles, the practice of invoking saints is somewhat derided, but the Oxford Movement led to a revival of the practice, which is now popular among High Church Anglicans.
Jewish views
There is some evidence of a Jewish belief in intercession, both in the form of the paternal blessings passed down from Abraham to his children, and 2 Maccabees, where Judas Maccabaeus sees the dead Onias and Jeremiah giving blessing to the Jewish army.
Muslim views
Tawassul is an Islamic religious practice in which a prayer is offered to Allah through an intermediary.
There is a difference of opinion amongst the Muslims regarding the practice. The Sufi, Sunni, and Shi'a muslims accept intercession at the levels of jurispudence and creed. The Salafi Sunni muslims approach the subject of intercession with extreme caution. In some cases Salafi Sunnis will call those who practice intercession (tawasul) disbelievers.