Rt Rev Roger Morris, Bishop of Colchester, has led messages of support for relatives following the incident Thursday afternoon, which is now being investigated by Essex Police.
Bishop Roger told Premier Christian Radio: "The shockwaves of an attack like this, particularly on a young and defenceless baby, is such that many people will feel a deep sense of grief."
Emergency services were called to a property on Harwich Road in Colchester soon after 3pm on Thursday where the infant's 22-month-old brother had also suffered life-changing injuries.
Rev Tim Platt from the Parish of Greenstead with St Anne, which includes St Matthew's Church on Harwich Road, told Premier: "Our hearts go out to the family at this time of tragic loss."
"We will be remembering them in our prayers at the parish church of St Andrew on Sunday and also all those currently caring for the brother and mother in hospital."
Praying for the family on Harwich Rd
— Roger Morris (@bishcolchester) October 14, 2016
May God sustain them in their anguish
and into the darkness of their grief bring the light of his love
It remains unclear which breed the dog was, however, it was subsequently seized and put down with permission of its owner.
Rev Ian Davies, a pastor from Kingsland Church in Colchester, told Premier: "I am not a parent, so I have no idea what those parents are going through but it's a very sad situation.
"Here, at Kingsland Church, we're a good praying church, and we shall be praying for the family. It's just important that we try to love people and look after people through this difficult time."
A woman also suffered minor injuries when she was bitten by the dog, while the family is currently being supported by specially trained officers.
24-year-old neighbour, Scott Mills, said: "When we heard that a baby had died, everyone was very upset. It's dreadful and so tragic."
Bishop Roger added: "[We can be] praying for that whole community and for that family, in particular, that somehow the light of God's love which in the darkness and despair and anguish of their suffering."
Figures show there have been 18 deaths from dog bites in England and Wales since 2012.
Click here to listen to Bishop Roger speaking with Premier's Alex Williams:
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Click here to listen to Rev Ian Davies speaking with Premier's Alex Williams:
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