17.111 – Praise (be) to God, who has not taken a son, nor has He any associate in the kingdom
The Quran denies that Allah has taken a son. This verse does not clarify the identity of the audience, and the rest of the sūra does not seem to be concerned with Christians. However, the same words appear in the inscriptions within the Dome of the Rock, built in AD 691, where they were likely intended to target the Christian majority in Jerusalem at that time.
In any case, the verse offers a strong suggestion of the reason for the denial. The concern is theological. Allah has no partner (sharīk) in his rule and no need for an ally (walīy). To say that he has taken a son seems to be considered a statement that impinges on Allah’s sovereignty. See “Son of God in the Quran” and a summary of verses that accuse the People of the Book of “associating” at 61.9.