At that time, Jesus called to him his twelve disciples and gave them authority over unclean spirits, to cast them out, and to heal every disease and every infirmity. These twelve Jesus sent out, charging them, “Go nowhere among the Gentiles, and enter no town of the Samaritans, but go rather to the lost sheep of the house of Israel. And preach as you go, saying, ‘The kingdom of heaven is at hand.’ Heal the sick, raise the dead, cleanse lepers, cast out demons. You received without paying, give without pay.” Matthew 10:1, 5-8
Cosmas and Damian were twin brothers who gave their money to the poor, setting aside only enough for themselves to devote their lives to the service of Christ in their neighbor. According to one account, they were born in Arabia and lived as adults in Syria before coming to Rome. Raised by devout Christian parents, they led chaste lives and were granted by God the gift of healing the sick. By their generosity and kindness to all, the brothers converted many to Christ. The brothers told the sick, “It is not by our own power that we treat you, but by the power of Christ, the true God. Believe in Him and be healed.” So strict were they in their determination not to accept any payment that, according to a legend, one brother refused for a time to speak to the other because the brother had accepted an apple.
Their life of service and their influence on the people around them led many into the Church, but also attracted the attention of the Roman authorities. When soldiers were sent to arrest the brothers, local Christians convinced them to hide for a while until they could arrange their escape. Unable to find the brothers, the soldiers instead apprehended other Christians. Cosmas and Damian then surrendered to the soldiers, asking them to release those who had been arrested in their place. The brothers were executed in Rome in 284 during the reign of the emperor Carinus. “We have done evil to no one,” they declared to the emperor. “We are not involved with the magic or sorcery of which you accuse us. We treat the infirm by the power of our Lord and Savior Jesus Christ and we take no payment for rendering aid to the sick, because our Lord commanded His disciples, ‘Freely have you received, freely give’.”
Holy Unmercenary is a title applied to a number of Christian saints who did not accept payment for providing physical and spiritual healing. And who, since their repose, continue to heal by their prayers those who call on them in faith.
Apolytikion: Sainted Unmercenaries and Wonder Workers, regard our infirmities; freely you have received, freely share with us.
Kontakion: Having received the grace of healing, you extend health to those in need, O glorious and wonderworking physicians. Hence, by your visitation, cast down the audacity of our enemies, and by your miracles, heal the world.
Readings today in the Orthodox Church: First Corinthians 12:27-31; 13:1-8, Matthew 10:1, 5-8
 Much of this account was taking from http://incommunion.org/?p=671