Authors:

Speak seldom, but to important subjects, except such as particularly relate to your constituents, and, in the former case, make yourself perfectly master of the subject.

George Washington (1835). “The writings of George Washington: being his correspondence, addresses, messages, and other papers, official and private, selected and published from the original manuscripts; with a life of the author, notes, and illustrations”, p.280
Speak seldom, but to important subjects, except such as particularly relate to your constituents, and, in the former case, make yourself perfectly master of the subject.