Post History

Why did John Knox reject the offer of the bishopric of Rochester?

In a [lecture on the historical background to the Westminster Standards](https://www.thegospelcoalition.org/course/the-westminster-standards/#course-introduction-history), around minutes 12–13, Sinclair Ferguson mentions that John Knox was offered the bishopric of Rochester, "whether to give him more scope for ministry or to silence him." Per [Wikipedia](https://en.wikipedia.org/w/index.php?title=John_Knox&oldid=987959176), the offer was given because Knox was seen as a "useful political tool."

Knox turned down the offer, but it's not clear to me what his motivation was.  Did he see it as an attempt to silence him or co-opt his ministry, or for some other reason?  Did he explain why in any surviving documents?  If not, is there a consensus among historians?