Philosopher and author on spiritual formation Dallas Willard has died at the age of 77.
His death comes just days after it was revealed he was battling stage 4 cancer.
Many Christians credit his works, notably "Divine Conspiracy", with helping them reinvigorate and rethink how they live out their faith.
Tributes have been pouring in on Twitter since news of his death emerged:
Rick Warren (@RickWarren)
A great saint, Dallas Willard,had gone on to heaven. Angels are rejoicing.
Mark Russell (@markrusselluk)
Gutted by Dallas Willard's death. He was a wonderful author and his books always challenged and inspired me
Fuller Seminary (@Fuller)
Our thoughts and prayers are with the family of Dallas Willard, who passed away today at the age of 77 after battling cancer.
World Vision (@WV_Churches)
Our prayers to his family RT @CTmagazine Dallas Willard died this morning, just days after announcing he had cancer
Other fans took to Twitter to express their appreciation for Willard:
Jon Soper (@jonsoper)
Dallas Willard, an exceptional follower of Jesus, died today. Learned so much from him.
Peter Ould (@PeterOuld)
RIP and Rise in Glory Dallas Willard. Heard him speak in Oxford years ago. Excellent chap.
Martin Saunders (@martinsaunders)
Oh no, Dallas Willard has died. What an incredible man. His writing has been formational for so many. Sad day
In a tribute on his Andy Unedited blog, InterVarsity Press associate publisher for editorial Andrew T Le Peau said many people would miss his "strong, gentle wisdom" and remember him as a person who was "soaked in the presence of Christ".
"He was a beloved friend and writer to many," he said.
Dallas Albert Willard was born on 4 September 1935 and educated at Baylor University, the William Jewell College and the University of Wisconsin-Madison.
Hear Dallas talk here on the topic of "What Skepticism is Good For" in one of his last public speaking engagements: