All the documents of Christianity - such as those that are found in the collection known as 'the New Testament' - were written in the common Koine Greek language of the Mediterranean world. In this video, Dr Peter Watts argues that learning to read that language, as part of a study of theology or of the Bible, is an important way not only to get a deeper appreciation of those texts but of gaining access to the mental worlds of the writers of those early texts which are still valued by Christians today.
Other videos that you may find useful;
Why Study Biblical Studies https://www.youtube.com/watch?v=V_MCWP7nJTA
Why Study Hebrew https://www.youtube.com/watch?v=z6K8KAuJnEU