Dictionaries of the Bible (or dictionaries of some portion of the Bible, such as the Old Testament or New Testament or of the Prophets or the Gospels, etc.) contain articles that define and explain biblical words, sometimes at considerable length.
The articles identify and describe people, corporate bodies, events, and themes in the Bible.
The articles also summarize, outline, and analyze the books of the Bible.
When you are writing on a passage in the Bible, you should begin by identifying key words, persons, events, corporate bodies, and themes that appear in your passage.
Then read about those words, persons, events, corporate bodies, and themes in biblical dictionaries to acquire a basic understanding.
This preliminary understanding will be helpful when you move on to research in commentaries, journal articles, and books related to your passage.