Theology is the study of God. No subject is more instructive and elevating in the whole realm of human thought. Little wonder that it is called “Queen of the sciences.” Based on the revelation given to mankind finally and perfectly disclosed in Jesus Christ, it surpasses all other sciences in its quest to know ultimate reality.
The word theology comes from two Greek terms, theos (God) and logos (discourse), thus literally meaning “God speaking.” This corresponds to the impulse within the nature of God to make himself and his purposes known. That inherent desire to communicate bespeaks his love, which gives rise to evangelism—bearing Good News. And what greater news can one hear than to learn of the love of God and his Redeemer Son, whom to know aright is eternal life.
In their origins, then, theology and evangelism belong together. When the two are separated in practice, as so often happens, both suffer loss—theology loses direction and evangelism loses content. To use the analogy of C. E. Autrey: “Theology is to evangelism what the skeleton is to the body. Remove the skeleton and the body becomes a helpless quivering mass of jelly-like substance.” Looking at it another way, J. I. Packer observes, when theology is separated from evangelism, “it grows abstract and speculative, wayward in method, theoretical in interest and irresponsible in stance.” Perhaps James Denny says it best: “If evangelists were our theologians or theologians our evangelists, we should be nearer the ideal, for evangelism is in the last resort the judge of theology.”
― Robert E. Coleman, The Master Plan of Evangelism