Sentence:  The Archbishops and Bishops, next under the King, have the government of the Church and affairs ecclesiastical: be not, Sir, a mean to prefer any to those places for any by-respect; but only such as for their learning, gravity, and worth are deserving: and whose lives and doctrine are and ought to be <WSD>exemplary</WSD>. 
Meaning of the word marked with <WSD> tags:  Of such high quality that it should serve as an example to be imitated; ideal, perfect.