The Archbishop of Wales will urge people not to be afraid, in an Easter message calling for strength following the "tragic events" in Brussels.
Amid heightened fears of a terror attack in the UK, Dr Barry Morgan will encourage people not to return "violence with violence".
He will acknowledge growing fears that Europe is being "inundated" by refugees, but say "not being afraid means resisting all that enslaves, degrades and dehumanises" others.
The Archbishop, who will speak at Llandaff Cathedral on Easter Sunday, will say: "Our world seems to be gripped by fear - to begin with there are constant threats of terrorist attacks on virtually every major city across the world.
"This country and London especially, is on high alert against such a possibility because it is regarded as a prime target. The tragic events in Brussels this week have simply reinforced the terror."
He will add: "At the same time, many countries in Europe are fearful of being inundated by refugees and there are plenty of people willing to fuel such fears.
"And the debate whether to remain or leave the European Union, as far as Britain is concerned, often feeds on people's fears - fears about sovereignty and not being able to decide Britain's future and again the financial implications of having to accept more refugees than we can afford."
Dr Morgan called on people to exhibit the Christian values of "forgiveness, compassion, mercy and grace" in the face of fear, by "turning the other cheek" and "valuing those who are least valued in society".
"Not being afraid means resisting all that enslaves, degrades, and dehumanises another human being and doing so non-violently", he will say.
The Archbishop of Wales will speak at a service at Llandaff Cathedral at 11am on Sunday. All are welcome to attend.