Do the Quranic verses that condemn the Christians' saying that God is one of three, such as verse 171 from Surah An-Nisa and verse 73 from Surah Al-Ma'idah, refer to the Christians' saying that God, Jesus, and Mary are three, as Ibn Kathir mentioned, or do they speak about the well-known doctrine of the Trinity (the Father, the Son, and the Holy Spirit)? And if the intention was to refer to the saying that Jesus and Mary are one of three, were these verses pointing to a specific sect of Christians? And did the Quran or the Sunnah condemn the doctrine of the Trinity that most Christians believe in (the Father, the Son, and the Holy Spirit), and what about their belief concerning the Holy Spirit?

"Indeed, disbelievers are those who say, 'Allah is the third of three.'" This refers to the disbelief of Christians due to their saying that Allah is the third of three, as they have taken the Messiah and his mother as gods. This is clear from verse 116 of Surat Al-Ma'idah, and also from verse 75 of the same surah, which demonstrates that Mary is not divine, for she was a truthful one and ate food.

And Allah Almighty says in Surat An-Nisa (171): "And do not say, 'Three.'" This means that Christians should not say their gods are three. It is understood from the sayings of the exegetes that the verse encompasses all forms of Christian trinity.

As for counting Mary among the three hypostases, this does not negate the fact that Christians deify her. Some sects explicitly declared her divinity, while others directed certain acts of worship to her, such as seeking aid and prostration.

As for the term "Holy Spirit" in the revealed texts, it refers to Gabriel, peace be upon him. This aligns with the story of Mary's conception of Jesus, peace be upon him, through Gabriel's blowing into her. However, Christians distorted the meaning of the Holy Spirit and said it is an attribute of Allah inherent in Him, which is the creative life. This is the root of their misguidance, based on the saying of Christ: "Baptize people in the name of the Father, and the Son, and the Holy Spirit." The revelation did not specifically refute this hypostasis independently, but the texts that state that Allah is One and Unique invalidate the essence of their belief regarding this hypostasis.