The terrorist attack on London Bridge last month is a theme of the Archbishop of Canterbury's Christmas Day sermon at Canterbury Cathedral.
During his sermon, he reflected on how darkness is to be found in other parts of the world as well as closer to home, with his thoughts being on the London Bridge attack, in which two people died.
Usman Khan killed 25-year-old Jack Merritt and 23-year-old Saskia Jones in the terror attack on London Bridge. Khan was shot dead at the scene by police.
During his sermon, the Archbishop reflected on his recent visit to Beni, in the Democratic Republic of Congo (DRC), where he visited health centres and workers tackling the deadly outbreak of Ebola there.
He reflected on the severity of Ebola in Beni, which he noted has been the "second worst outbreak" of the virus, with at least 3,000 people dead.
At the same time, he paid tribute to the dedication of the area's bishop in helping those affected.
"Its Anglican bishop is alight with Christ, always present, always giving of himself," he said.
He continued: "Darkness is a monster that lies. Its growling claims seem to call out with a louder volume than the love filled whispers of light. We see the shadows out of the corner of our eyes.
"They may be violence as in the Congo or on London Bridge. They may be political. They may be purely personal, from family feuds, relationship problems, illness.
"The darkness within us that sometimes seems to threaten our certainty and hope. And whether solid or illusion, they are the reality with which we live.
"By contrast we do not see light, but we do see truth in light."
The Archbishop's Christmas Day sermon echoes his ecumenical Christmas letter to Church leaders this week in which he said that "life is fragile", with "countless" people "threatened by war, disease, climate change, poverty and natural disaster".
In his letter, he recalled his visit to the DRC where he witnessed the "twin threats" of war and Ebola.
"I found there a church in good heart: proclaiming the good news of the coming of God in Jesus Christ and caring for those in need," he said.
"The church there is working, in the power of the Holy Spirit, to bring hope of life in all its fullness."
He also recalled a prayer retreat with the Pope earlier this year for peace in South Sudan. He said that he and the Pope would make a joint visit to the country next year "once a government is in place".
