Christians often accuse Muslims of not even knowing what the Trinity is, pointing out that the Qur’an sets it up as Allah the Father, Jesus the Son, and Mary his mother. While veneration of Mary has been a figment of the Catholic Church since 431 when she was given the title “Mother of God” by the Council of Ephesus, a closer examination of the verse in the Qur’an (5:116) most often cited by Christians in support of their accusation, shows that the designation of Mary by the Qur’an as a “member” of the Trinity, is simply not true.
While the Qur’an does condemn both trinitarianism (the Qur’an 4:17) and the worship of Jesus and his mother Mary (the Qur’an 5:116), nowhere does it identify the actual three components of the Christian Trinity. The position of the Qur’an is that WHO or WHAT comprises this doctrine is not important; what is important is that the very notion of a Trinity is an affront against the concept of One God.
The following is an excerpt from a webpage:
a) The word “Trinity” appears in the Holy Qur’an in verses 4:171 and 5:73. In these two verses the name of Mary is not mentioned as “the third Person of the Holy Trinity”. Not withstanding that as an argument, here are the observed facts.
b) The carved or molten images and/or statues of Jesus Christ and his mother Mary, in various sizes and shapes, are to be found in the Catholic and Orthodox Churches, all around the world.
c) Most of these Sacred Statues or Images are placed in the prominent places of the Prayer Halls of these Christian Churches for the purpose of venerating and worshipping of these entities.
d) One would also notice that the majority of the attending congregates would kneel, worship, venerate and pray before these Holy Images as their reverent rituals and inherited traditions. Many devoted believers would place lighted candles in front of these Sacred Statues or Images before worshipping or paying their homage to them.
e) These Catholic and Orthodox congregates who venerate Lord Jesus as their God and Virgin Mary as the “Mother of God”, do form the bulk of the Christians community. It has been so since the inception of the Roman Catholic Church. The Protestants, who separated from the Roman Catholics, nearly ten centuries after the advent of Islam, do not have the Statues of Mother Mary in their Churches.
f) In 1998, according to the Encyclopedia Britannia there were 1040 million Catholics and only 361 million Protestants.
g) These observations clearly indicate that Virgin Mary has been venerated with hyperdulia, along with her son Jesus, by the majority of the Christians, from the early years of the Catholicism.
h) As for the Holy Ghost, the third person of the Holy Trinity, no Christian Church has so far instituted its venerating representation, image or semblance for their Churchgoers.
The obvious conclusion is that for all practical purpose and in reality, when the issue is of Worshipping, Venerating, Deifying and/or Idolizing, it is Mary - the "Mother of God" and not the Holy Ghost has that kind of rank and status. Briefly, the historical figures of Jesus and Mary are venerated as Deities. The Holy Ghost is not venerated as a Deity.
And BTW, there are hardly any meaningful differences between Catholicism and Protestantism worth even thinking about as far as Muslims are concerned.
And whoever desires a religion other than Islam, it shall not be accepted from him, and in the hereafter he shall be one of the losers.