The journals reveal Charles' grave concern about a possible split between the Methodists and the Church of England. (Charles, of course, vowed to stay with the Church of England if such a split were to ever occur.) The journals also speak (disapprovingly) of his brother, John's, plans to marry. As well as Charles' concerns about the spread of Islam.
The conservative Anglican review, of course, draws some parallels between the Methodist/Church of England split and the current concerns about an Anglican split.
The original article published by Telegraph.co.uk can be viewed here.