Apostle Duncan began to cultivate himself in God's word under the ministry of the Faith Healing Center, Deptford, New Jersey. He worked faithfully in every avenue as a local minister concerning his theological education. He was appointed Assistant Pastor of the Faith Healing Center in 1969. In 1970, he became the Pastor of that ministry .
In 1971, by the leading of the Lord, Apostle Duncan was released of his Pastorship in New Jersey and moved to Coatesville, Pennsylvania.
After Apostle Duncan and his family arrived in Coatesville, prayer meetings were held in his apartment on North 7th Avenue, across the street from his former business, "Duncan's Barber Shop".