TOM O'Gorman's death is a "shocking why, without an answer", mourners were told at his removal.
But UCD chaplain Fr John McNerney stressed the need for forgiveness and revealed that Mr O'Gorman had always carried with him a photograph of 'The Pardon', which depicted Pope John Paul visiting his assailant in prison.
The religious researcher, who had studied arts and literature at UCD, lost his life after a row at his home in Castleknock last week.
A 34-year-old Italian man, Saverio Bellante, has been charged with murdering Mr O'Gorman.
Fr McNerney told mourners that 39-year-old Mr O'Gorman himself would have suggested that they "see behind the horror" of his death.
A copy of the Gospels was laid on the coffin, with Fr McNerney explaining that the deceased had "cherished" the Gospels and had tried to live them in his every day life.
While his family and community are in "total shock" at this heartbreak, he said that in the midst of this "horror" they may recall the sentiment: "Father forgive them, they known not what they do."
At the last public talk Tom had given, he had prayed "Jesus, forgive them".
"Isn't this a word from Tom for us?" Fr McNerney questioned, even in the circumstances of his violent death.
Mr O'Gorman had always "easily identified" with those living on the "existential margins of life", Fr McNerney continued.
He later said the mourners were not saying goodbye to him but "arrivederci – see you in Paradise".
A poem, written by a friend in tribute, began: "What makes it so unbearable is the manner of your leaving; an unspeakable act of momentary madness took our brave knight away."
Mourners heard of his "volcanic enthusiasm", his "inner thirst for rich relationships" and his passion that people "measured up to the truth".
A hushed candlelight vigil was held as the coffin arrived at Our Lady Mother of the Church in his native Castleknock in Dublin last night for the removal, with hundreds of mourners attending.
They included senator Ronan Mullen, Bishop Ray Field of Dublin, Martin Long of the Catholic Communications Office, and John Waters.
Mr O'Gorman's sister Catherine and brother Paul were deeply distressed throughout the service.
The siblings were deeply overcome by the beautiful, plaintive French vocals of his favourite song, 'Ma Toute Belle'.
The coffin was carried into the church by friends of the deceased, including David Quinn, a colleague at the Iona Institute. The funeral takes place today at 11.30am.