A Bible commentary . Commentaries include background scholarship on the books of the Bible. They will help you understand the Bible better. A good one volume Bible commentary is affordable. Ask your clergy for one that is appropriate for a United Church context.
Some commentaries are overly evangelical or fundamentalist in perspective.
Get a good mainline commentary. Church Library . Suggest that your congregation have available in your church library, a full multi-volume modern commentary. Full volume commentaries go into much greater depth than a one volume commentary obviously can. These are expensive, but since Scripture is central to our lives, this is a resource that is well worth investing in.