Search this entire site for webpages containing phrases or words you enter. 

You will then be directed to the google.com search engine's advanced search screen.

Then use additional features of the advanced search page like keying in the 'Find results section'.

As long as you leave 'nepaugchurch.org' in the text field with caption 'return results from the site or domain' you will be searching only the Nepaug Bible Church website.