Denver R. Q. Callahan was born July 7, 1926 at Sallisaw, OK, He began his pastoral ministry in Sultana, CA, while he was in his early twenties. Later, he planted a church in Sunnyslope, AZ. He also served as the Youth Director for the state of AZ with the Pentecostal Church of God.

Dr. Callahan and his wife, Charlean, then moved to and pastored in Paris and Alma, AR, before accepting the pastorate of the K Street Pentecostal Church of God in Muskogee in 1962. At this church, he started a large daycare and later built a new building on D and Independence known as Grace Cathedral. It was at this location that he also founded Pentecostal Academy Center, a Christian school. After outgrowing this facility, the church purchased property on Peak Blvd. and build Grace Cathedral which is now known as Oasis Community Church. After 29 years of successful ministry with this congregation, Dr. Callahan spent the next five years working with the Pentecostal Church of God in the education field traveling throughout five different states.

He also ministered throughout the years in South Africa, Ghana, Russia, and 27 other foreign countries building schools, putting in water wells, and starting churches. He also led many trips to the Holy Land. In addition, Dr. Callahan was a respected minister for camp meetings, minister’s retreats, youth camps, marriage retreats, men’s seminars and educational and Bible conferences in the United States.

In 1997, a need was presented to him for another ministry in Muskogee. Moving forward in that vision, Abiding Life Fellowship was birthed. He spent the next 17 years serving and ministering to this congregation. He resigned the church in the summer of 2013 with his final service at Abiding Life on Sept. 3, 2013. Pastor Callahan joined the heavenly hosts on April 22, 2014.