"Jesus Christ is the beginning, the middle, and the end of all. In the Gospels he walks in human form upon the earth, and accomplishes the work of redemption"

Philip Schaff's quote is an extensive statement encapsulating the central function of Jesus Christ in Christian theology. To interpret this, we should look into the doctrinal significance of each aspect Schaff points out.

First of all, the notion that "Jesus Christ is the start, the middle, and the end of all" echoes the scriptural referrals to Christ as the Alpha and the Omega, terms derived from the very first and last letters of the Greek alphabet. This recommends that Christ is eternal, present at the production of deep space and at its ultimate conclusion. In Christian understanding, Jesus is not merely a part of historic events but transcends time and is integral to the whole cosmic narrative. He is considered the Creator, Sustainer, and Consummator of all creation.

In the middle part of Schaff's quote, he describes Jesus as strolling "in human type upon the earth" as illustrated in the Gospels. This underscores the teaching of Incarnation, where Jesus, thought to be both totally magnificent and completely human, got in human history. The Gospels-- Matthew, Mark, Luke, and John-- information Jesus' life, mentors, death, and resurrection. These accounts are main to Christianity as they represent Jesus not simply as a spiritual leader however as God incarnate who lived among humanity, sharing in their sufferings and experiences.

Last but not least, Schaff discusses that Christ "achieves the work of redemption", symbolizing the belief that through Jesus' death and resurrection, humanity is used salvation. The principle of redemption is core to Christian faith: it recommends that Jesus' sacrifice on the cross reconciles humankind with God. This act is viewed as the fulfillment of Old Testament predictions and the cornerstone of Christian soteriology, which is the study of religious doctrines of salvation.

In summary, Schaff's quote encapsulates the essential Christian belief in Jesus Christ as the everlasting figure who initiates, takes part in, and culminates the magnificent plan for mankind's redemption, serving as a centerpiece for faith, commitment, and the Christian understanding of history.