Context: John Selden, apparently believing that ministers of the gospel are not always given to following their own good advice to their flocks, quotes "Do as I say, not as I do." His contention is that one's practice should correspond exactly with his preaching. The same idea has been advanced by Bartholomew Young (with George Pettie) in The Civil Conversation of M. Stephen Guazzo (1586): "Take you no heed to that which I do, but mark that which I speak." James Mabbe in translating Celestina (1631) says: "Do you that good which I say, but not that ill which I do"; this version clearly indicates that one's advice is always better than his actions. Selden admirably illustrates his idea by indicating that a physician who prescribes one course of treatment for a patient and a different one for himself would do little to inspire confidence in his patients. As he puts it:
Preachers say, "Do as I say, not as I do." But if a physician had the same disease upon him that I have, and he should bid me do one thing and he do quite another, could I believe him?