After working in Winnipeg for some years, and being ordained to the ministry, he moved to Jerusalem in 1935 having received a "call from God" during a service at Zion Apostolic Church.
The Reverend Hull devoted the next twenty-seven years to missionary work in Jerusalem.
In 1947, Hull significantly influenced Justice Ivan C. Rand (1884–1969), the Canadian member of the United Nations Special Committee on Palestine, to understand and positively support the United Nations Partition Plan for Palestine, which was among the factors in the creation of the State of Israel.
Hull returned to Canada later that year and wrote The Struggle for a Soul about his experiences with Eichmann.
He died September 1, 1992, and was interred with his wife, in Oakwood Cemetery, Simcoe.