Systematic Theology is the study of what the whole Bible has to teach about any given topic. All the places where Scripture speaks about an idea, a word, or teaching, Systematic Theology attempts to organize them into a concise understanding or conclusion about what all the passages teach.
A unified and whole understanding is the goal. The different passages are identified, grouped into themes, analyzed, and finally summarized into a conclusion about what the Bible says about the matter.
Systematic Theology answers the question: What does the Bible teach about _X_?