The Service of Supplication (Paraklisis)
The Service of Supplication, which is also known as Paraklisis, is one offered especially at times of sickness, temptation, or discouragement. The various prayers ask the Lord for guidance, personal strength, and healing. Many of the hymns and prayers are directed toward Mary, the Theotokos, and they ask for her assistance. Orthodoxy affirms that each of us, with Mary, the Saints, and the faithful departed is united in a bond of faith and love in Christ. Therefore, just as in this life we can turn to each other for prayer, the Church believes that we can also turn to Mary - the human being closest to God - and ask her to pray to God for us. This belief is expressed in the hymn which says:
"O never failing protectress of Christians and their ever-present intercessor before the Creator; despise not the petitions or sinners who have recourse to you, by your goodness extend your help to us to call upon you with confidence. Has O Theotokos, to intercede for us, O who have always protected those who honor you."
There are two forms of the Service of Supplication: the Greater and the Lesser. It is Lesser Service of Supplication which is briefer and the one most frequently offered. Both forms of the Service are offered during first fourteen days of August which precedes the Feast of the Dormition of the Theotokos celebrated on August 15th.
Source: Greek Orthodox Archdiocese of America, http://www.goarch.org/ourfaith/ourfaith7052.