Thomas Arnold writes in his book the spread of Islam in the world:
A later generation attributed to 'Umar a number of restrictive regulations which hampered the Christians in the free exercise of their religion, but De Goeje [3] and Caetani [4] have proved without doubt that they are the invention of a later age; as, however, Muslim theologians of less tolerant periods accepted these ordinaces as genuine, they are of the importance for forming a judgement as to the condition of the Christian Churches under Muslim rule. This so-called ordinace of 'Umar runs as follows: "In the name of God………. you are at liberty to treat us as enemies and rebels". [5]
[1] Baladhuri, p. 129 [Liber Expugnationis Regionum]
[2] Ibn S'ad, Vol. III, p. 246 [Al-Tabaqat]
[3]Memoire sur la conquete de la Syrie, p. 143
[4] Annali dell' Islam, Vol. III, p. 957.
[5] Gottheil pp. 382-4 [Dhimmis and Moslems in Egypt]
Abdulaziz Sachedina writes in his book The Islamic Roots of Democratic Pluralism:
The discriminatory regulations in exchange for protection are usually traced back to a document known as the Pact (pahd) of 'Umar. The contents of this document suggest that its attribution to Umar b. al-Khattab, who ruled from 634 to 644, is doubtful. The discriminatory stipulations—a non-Muslim's word was not to be accepted against a Muslim in the qadi's court; the murder of a non-Muslim was not to be treated as quite so heinous a crime as the murder of a Muslim—not only run completely counter to the spirit of justice in the Koran, but they also contravene the practice of the early community. The tendency among later jurists, in the eighth and ninth centuries, was to seek justification for the eighth-century rulings by ascribing the documentary evidence in support of these rulings to the early community, whose prestige in such matters was a source of authentication for the later jurists' extrapolations. Thus, for instance, the prohibition against building new churches or repairing old ones, which was instituted under some Umayyad and 'Abbasid caliphs, did not prevail in the early decades, because it is well documented that non Muslims erected such places of worship following the conquest. When Muslims took Jerusalem in 638, the caliph 'Umar b. al-Khattab, on his visit to that city from Damascus, sent the inhabitants of the city the following written message:
In the name of God, the Merciful, the Compassionate. This is a written document from 'Umar b. al-Khattab to the inhabitants of the Sacred House (bayt al-maqdis). You are guaranteed (aminun) your life, your goods, and your churches, which will be neither occupied nor destroyed, as long as you do not initiate anything [to endanger] the general security
It is difficult to see how the same caliph could have instituted the discriminatory laws against the protected people, as later sources report.