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The way I see it is both Christianity and Islam are right and wrong in their theological beliefs. The contradictions are perceived rather than real. They are derived from interpretation and misunderstandings about sacred writings rather than any problem with either the Bible or Quran. Both Christ and Muhammad were Manifestations of God Himself in that both revealed His purpose.The easiest example is the two verses in the Quran that refer to Christ’s crucifixion.
Surah 4:157-158 says:
“. . . they [the Jews] said (in boast), ‘We killed Christ Jesus the son of Mary, the Messenger of Allah’ – But they killed him not, nor crucified him, but so it was made to appear to them, and those who differ therein are full of doubts, with no (certain) knowledge, but only conjecture to follow, for of a surety they killed him not – Nay, Allah raised him up unto Himself . . . .”
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This would be best understood allegorically rather that literally. They killed him but they did not kill His Spirit.