The Abrahamites were a sect of deists in Bohemia in the 18th century, who professed to be followers of the pre-circumcised Abraham. Believing in one God, they contented themselves with the Decalogue and the Paternoster. They believed in one God, but rejected the Trinity, original sin, and the perpetuity of punishment for sin, and accepted nothing of the Bible except the Ten Commandments and the Lord’s Prayer. Declining to be classed either as Christians or Jews, they were excluded from the edict of toleration promulgated by Emperor Joseph II in 1781, and deported to various parts of the country, the men being drafted into frontier regiments. Some became Roman Catholics, and those who retained their “Abrahamite” views were not able to hand them on to the next generation.
They are not to be confused with the ninth century Syrian sect also known as the Abrahamite monks, who were exterminated for idolatry by the emperor Theophilus.
ABRAHAMITES. An order of monks exterminated for idolatry by Theophilus, in the ninth century. Also the name of another sect of heretics who had adopted the errors of Paulus. See PAULICIANS.
[Buck]
(1) Syrian heretics of the ninth century. They were called Brachiniahby the Arabs, from the name of their head, Ibrahim, or Abraham of Antioch. They denied the Divinity of Christ, and were looked on by some as allied to the Paulicians.
(2) A sect of Bohemian Deists. They claimed that they held what had been Abraham’s religion before his circumcision. They believed in oneGod, but rejected the Trinity, original sin, and the perpetuity ofpunishment for sin, and accepted nothing of the Bible save only theTen Commandments and the Lord’s Prayer. On their refusal to adopt some one of the religions tolerated in Bohemia, Joseph II banished them to Transylvania in 1783. Some became converted later on to theCatholic Faith. There are still found in Bohemia some whose religiousbelief suggests that of the Abrahamites.
(3) Martyrs in the time of the Byzantine Emperor Theophilus, when apersecution of Catholics took place on account of the revival of theheresy of the Iconoclasts. At this time there was a monastery ofmonks in Constantinople called St. Abraham’s. When the Emperor called on them to renounce the cult of holy images they defended the practice with great zeal, and were consequently subjected (832) tomartyrdom.
[Catholic Encyclopedia]