Rev. Eiermann helped the church through a season of disorganization and spiritual depression into a season of enthusiasm. Rev. Oberkircher was installed as pastor and served for over twenty years. Updates continued with lighting fixtures being added and our ornate pulpit was installed by Dr. Edwin Jarecki of Philadelphia in memory of his mother. The denomination also went through changes as The Evangelical Synod of North America merged with the Reformed Church in the United States to form The Evangelical and Reformed Church. Our Ninetieth Anniversary History describes the denomination, "The Evangelical and Reformed Church, true to its name, believes in the Bible. It believes that the Bible is the Word of God, that God hath spoken and revealed Himself in His Word and in Jesus Christ the Word made flesh." After Rev. Eiermann's resignation there was a season of pulpit supply until the calling of Rev. Tepas in 1940.
As many churches at the time experienced, Saint Paul's saw great growth in membership following World War II, but also saw many of the German families begin to spread out through the region during an era of suburban sprawl and white flight. The German traditions of the church became more of a history than an identity. The church began a ministry supporting Back Bay Mission in Biloxi, Mississippi, and Eden Theological Seminary. St. Paul's hosted YMCA Forum Series and participated with Erie churches in voting drives. An Usher's Society was formed with an an annual communion breakfast. There were ministries to support Army Chaplains. Family ministries grew with a Boy Scouts Troop, Junior Choir, Married Couples Club, and Family Nights. In the 50s, this all led to a need for our Sunday School building to be expanded. Other innovations included a steam furnace and radio broadcasts. Rev Kratz lead through much of this season from 1951-1961. His slogan was "TEACHING-REACHING-PREACHING". He was elected a member of the General Council of the denomination as it was forming.
In 1957, The Evangelical and Reformed Churches saw another merge, this time with the Congregational Christian Churches and Afro Christian Convention to become the United Church of Christ. The churches remain independent and autonomous, with a shared belief in the divinity of Christ and the Trinity. Beliefs otherwise vary greatly with the motto from John 17:21, "That they all be one." Many still hold to historic confessions, in either from the Puritan Congregationalist Churches or German Reformed Churches.