His journey changed drastically in 1920 when, after a severe leg injury and the development of blood poisoning, he was instantly healed through the prayers of Pentecostal friends. This experience, followed by his baptism in the Holy Spirit, led him to found Southwestern Bible School (now Nelson University ) and dedicate his life to teaching "the whole gospel for the whole world".

Dr. Nelson served as the president of what is now known as (formerly Southwestern Assemblies of God University) in Waxahachie, Texas. His academic rigor, combined with a deep reverence for Scripture, positioned him as a bridge between traditional Reformation theology and the burgeoning Pentecostal movement of the early 1900s.

Nelson emphasizes that the Bible is the inspired, infallible Word of God and the final authority for all Christian faith and practice.