It is reported that Father Frans van der Lugt was killed by an unknown sniper in April 2014 at his home in Homs.
Christian charity, Aid to the Church in Need said that the Dutch Jesuit had lived in Syria for more than 40 years and was based in Homs, caring for the Christians trapped in the Old City during a siege that lasted three years.
Fr Ziad Hilal said the Vatican "should consider making Fr Frans a saint".
He had worked with Fr van der Lugt from 2009 until his death.
He said his life and work was "like Mother Teresa".
Fr Hilal said: "I spoke to him by phone about two weeks before his assassination.
"I said to him: 'Why are you still in the Old City of Homs? Many others have left but not you.' He replied: 'I am here to protect the Christianity spirituality in the area. I am the only priest here now.'
"I was surprised because Fr Frans did not normally speak this way. It was unusual for him to mention the crisis in Syria so directly."
Fr van der Lugt provided pastoral and practical help to around 75 Christians trapped in Homs Old City.
Fr Hilal stressed that Fr van der Lugt - the "saintly man" - always put others' needs before his own: "People are already calling him a saint. One deacon has made an icon of him."
