Some further explanations :
Grammatical context involves a natural, accurate understanding of the language of the original text which provides parameters for how language functions and which meanings are possible and probable for a given text. This is what most naturally comes to mind when translation work is done. It is the primary work of the translator to determine what meaning is expressed in the original language and how that can best be expressed in the target language. Grammatical context is the most important because it deals with the nuts and bolts of the language which convey meaning.
Historical context involves an understanding of the peoples, cultures, customs, and history of the times in which the Bible was written. As with the grammatical context, the historical context provides parameters for understanding the meaning of passages in the Bible and how they should be translated. It looks at the historical background and events of the text to provide a good balance for possible interpretations and meanings of a text.
Theological context is the understanding of God and his work that a particular author would have at the time he wrote a particular passage of scripture. In a manner similar to historical context, theological context provides parameters for deciding upon the meaning of a text and the best way to translate it. The Bible was written over a period of about 2,500 years. During this time, theological understanding changed dramatically. Moses did not know and understand God the way Paul did. This does not mean that Moses knew God in a wrong way and that Paul knew him the right way; it simply means that God had revealed more about himself over time, so Paul had a fuller understanding of who God was and what he was doing in the world.
by Dave Smith, D.Min.