Pastor Barnwell accepted his call to preach in 2006. Immediately, after accepting his call to preach the gospel in 2006, he enrolled in Luther Rice Seminary for preparation into the ministry. Pastor Barnwell graduated from Luther Rice Seminary with a Master of Divinity in May 2010. He also has two years of Ph. D studies at Baptist Bible Seminary in Clarks Summit, Pennsylvania.

Pastor Barnwell has a love for the local church. He is a proponent that every believer should serve the Lord in some capacity within the local church or outside the local church. He has served in many ministries in the church: music ministry, youth ministry, deacon ministry, evangelism ministry and jail ministry. In 2009, God laid upon Pastor Barnwell’s heart to plant a church to reach people who were far from God and lead them to a personal knowledge and relationship with Jesus Christ. Pastor Barnwell was the Senior Pastor and Founder of Grace Christian Church. On August 9, 2009 the Grace Christian Church held their first service and faithfully loved and served the Lord until God was doing a new thing. On August 9, 2020, Quincy was called to Philadelphia Baptist Church and was installed as the Senior Pastor. The two churches made a decision to merge together.  Continuing to listen to the voice of God, wanting to make an IMPACT on the community and the body of Christ, Philadelphia Baptist Church became Impact Community Church on January 8, 2023. Praise be to God!

Pastor Barnwell and his wife, Erika have been married since 2005. They have two boys: Quincy II and Caleb. Away from the pulpit, Pastor Barnwell enjoys exercising, swimming, playing basketball, playing the piano, reading, and spending time with his family.