The head of the Scottish Episcopal Church has said it is "deeply distressed at the widespread offence that has been caused" by a reading from the Quran at St Mary's Cathedral.

The Epiphany service at the Glasgow church included a contribution from Muslim law student Madinah Javed, who went beyond the reading included in the order of service to include extra verses explicitly denying Jesus was the son of God. It is not clear whether the dean, Kelvin Holdsworth authorised the extra verses or whether he was unaware Javed had recited the controversial passage.The incident has been widely condemned.

Bishop David Chillingworth said the SEC had a long commitment to interfaith work but that "This work, like all works of reconciliation, must be founded on truth. We approach others with open hearts but we stand in the truth of the gospel of our Lord and Saviour Jesus Christ."

In an implicit criticism of Holdsworth and St Mary's, he continues: "Those who seek to work in the area of interfaith relationships must weigh carefully whether the choices which they make are appropriate or otherwise. In today's world, those judgements must give careful consideration to good relationships which have been carefully nurtured over many years in a local context. They must also weigh carefully the way in which national and international issues shape perceptions of what is appropriate or inappropriate."

While Chillingworth says the SEC is distressed at the offence that has been caused, he also says it also deeply regrets "the widespread abuse which has been received by the Cathedral community". He says the Church will explore how interfaith work "can be carried forward in ways which will command respect", concluding: "Our desire is that this should be a worthy expression of the reconciliation to which all Christians are called."

In a blog post on Friday, Holdsworth – who has declined to comment for Christian Today – wrote: "No-one pretends that Muslims and Christians believe the same things. We know that Muslims don't believe in the divinity of Christ – that's a known and accepted fact. It isn't surprising."

However, he said accounts of the service had stirred up "the most incredible pot of hatred I've ever encountered". He continued: "This same Quranic reading has been given before in services and no outcry has happened. Is it because this is in a cathedral run by a gay man? Is it because the recitation was given by a young woman? Clearly those things are factors as they feature in some of the abuse."

He denied charges of synchretism, saying: "Syncretism means the amalgamation of different religions or cultures. We simply are not in that business when we do our interfaith work. We hold fast to Christian orthodoxy and we welcome those who come in peace."