The Greek words ‘logy’ and ‘Theo’ basically mean ‘God’ and ‘study’. In practice the word really means the systematic study of God and the nature of religious beliefs, or just the study of the divine.
The study of the divine might be undertaken for many reasons. One reason is to increase our knowledge of the Bible and see how it all fits together; some people would extend this practice to spiritual matters outside the Bible. The emphasis here is on systematic study and the coherence of the material. Other reason for studying theology would be to defend a religious tradition, or to separate Biblical ideas from latter traditional practices. Some might want to compare religious traditions. Others might want to find a biblical answer to a present situation. Else, individuals might want to challenge a biblical idea, or interpretation thereof, in order to justify something that others consider to be in opposition to tradition or the Bible.
Is it not uncommon for people to feel theology is very much divided from religion or spirituality. People may feel that theology is dry and detached from its subject matter as a map is detached from the territory it purportedly represents. Such an understanding fails to realize that a map can be used to better appreciate the territory, that the two need not be separated. Nonetheless it is quite possible to be so concerned with the map that one forgets there is a territory. It is also possible to falsify a map because one does not like aspects of the real world. Theology can end up detached from the reality of its subject matter, and people are right to be concerned with this.
Theology is supposed to be concerned with a truth, the truth of God’s creation. A deeper understanding of the truth is always a good thing, even if people sometime prefer to be dishonest with themselves. When theology is used as sophistry, when it tries to misrepresent truth and reality and make a misconception or lie appear convincing, then it contradicts the very thing it aims to study.
A property of truth is that it is coherent; no part of a coherent thing can contradict itself. If a theology gets something wrong, if an individual is not honest about a minor thing, then contradictions start to appear in any deeper understanding of the topic. Mistakes and misconceptions can be the result of dishonest or plain honest misunderstandings, but once an error is part of system it is very difficult to make the system coherent, and a non-coherent system cannot represent any coherent truth.
Every theology from the most simple to the most advanced acknowledges God as infinite. As such, there is no way an infinite mind can comprehend God because the finite can never fully comprehend the infinite. Out earthly understanding will always be less than the later ‘glory that will be revealed to us.’ [Romans 8:18]