Gospel Q&A

About

Ministry

Cornerstone

“So then you are no longer strangers and aliens, but you are fellow citizens with the saints, and are of God’s household, having been built on the foundation of the apostles and prophets, Christ Jesus Himself being the corner stone.” —Ephesians 2:19–20

Our name, “Cornerstone,” reminds us that our lives on earth and hope in heaven are built on Christ, the Cornerstone. We desire to provide opportunities for growth at both the personal level and within our church family as we strive to live as a church built on the person and work of Jesus Christ.

Teachers

Nathan Busenitz

Nathan Busenitz was unanimously affirmed as pastor-teacher of Grace Community Church on August 20, 2026. He began teaching at The Master’s University in 2000 and served as a full-time member of the pastoral staff at Grace Community Church from 2003 to 2009. In 2008, he began teaching historical theology at The Master’s Seminary and became a full-time faculty member the following year. In 2021, the TMUS Board of Directors appointed him executive vice president of The Master’s Seminary.

For many years, Nathan also co-pastored the Cornerstone Fellowship, where he taught, counseled, and discipled members of the Grace Church family. He later served as interim pastor of Grace Church before being appointed pastor-teacher.

Nathan and his wife, Beth, have four adult children, and two granddaughters.

Mark Tatlock

Prior to being appointed to his full-time role with TMAI, Dr. Tatlock served as Executive Vice President and Provost of The Master’s University. Mark brings 17 years of executive administrative experience to TMAI, and has been active in theological training for cross-cultural ministry within urban and international contexts. He is eager to invest in strengthening TMAI’s development and academic divisions. As a graduate of The Master’s Seminary, he is committed to TMAI’s theological distinctives and the priority of pastoral training. Mark and his wife Lisa have five children: Jacob, Josiah, Hope, Paul, and Olivia. Care for orphans and foster children is an area of personal concern for them both, believing that God would have His people model the amazing picture of the Gospel and of His love that is found in adoption.

Ben Trowbridge

Marco Bartholomae

Marco was born and raised in Berlin, Germany, where he worked and studied at the European Bible Training Center (EBTC) from 2007 to 2021. He was also part of a church plant in downtown Berlin in 2016 (Eckstein Gemeinde Berlin), where he served as the teaching and administrative pastor. Marco earned his MDiv and ThM degrees at The Master’s Seminary (TMS) and has been certified through the Association of Certified Biblical Counselors since 2014. He serves as the Vice President of Membership & Field Development at The Master’s Academy International (TMAI) in Los Angeles, California. He also assists Pastor Brad Klassen in the men’s ministry of Grace Church, Men of the Word. Marco is married to Katrina and they have four children.