In the ninth century during the time of the Iconoclasts, St. John of Damascus (December 4) was zealous in his veneration of holy icons. Because of this, he was slandered by the emperor and iconoclast Leo III the Isaurian (717-740), who informed the Damascus caliph that St. John was committing treasonous acts against him. The caliph gave orders to cut off the hand of the monk and take it to the marketplace. Towards evening St. John, having asked the caliph for the cut-off hand, put it to its joint and fell to the ground before the icon of the Mother of God. The monk begged Our Lady to heal the hand, which had written in defense of Orthodoxy. After long prayer he fell asleep and saw in a dream that the All-Pure Mother of God had turned to him promising him quick healing.
Before this the Mother of God bid him toil without fail with this hand. Having awakened from sleep, St. John saw that his hand was unharmed. In thankfulness for this healing St. John placed on the icon a hand fashioned of silver, from which the icon received its name "Of Three Hands." (Some iconographers, in their ignorance, have mistakenly depicted the Most Holy Theotokos with three arms and three hands.) According to Tradition, St. John wrote a hymn of thanksgiving to the Mother of God: "All of creation rejoices in You, O Full of Grace," which appears in place of the hymn "It is Truly Meet" in the Liturgy of St. Basil the Great.
St. John Damascene accepted monasticism at the Monastery of Saint Savvas the Sanctified and there bestowed his wonderworking icon. The Lavra presented the icon "Of Three Hands" in blessing to St. Sava, Archbishop of Serbia (+ 1237, January 12). During the time of an invasion of Serbia by the Turks in the reign of King Urosh V, some Christians who wanted to protect the icon entrusted it to the safekeeping of the Mother of God Herself. They placed it upon a donkey to lead the army into battle, which instead without a driver proceeded on its own by another route to Mount Athos and stopped in front of the Hilandari Monastery which is Serbian. The monks put the icon in the monastery's cathedral church (katholikon). During a time of discord over the choice of abbot, the Mother of God deigned to head the monastery Herself and moved miraculously from the sanctuary, and from that time Her holy icon has occupied the abbot's throne in the temple. At the Hilandari Monastery there is chosen only a vicar, and from the holy icon the monks take a blessing for every obedience. Thus even though the Hilandari brotherhood is a coenobium, it has no abbot and is administreted in accordance with the system of idiorrhythmic monasteries.
This event is commemorated by the Church on June 28 and July 12.
There are three sermons by St. John of Damascus on the Dormition of the Theotokos. They can be read here: Sermon One, Sermon Two, Sermon Three.