Please explain the following extract from Act I, scene ii of Shakespeare's As You Like It in detail.
Touchstone: "Of a certain knight........ yet was not the knight forsworn." Please explain this extract indetail.
No, by mine honour, but I was bid to come for you.
Where learned you that oath, fool?
Of a certain knight that swore by his honour they
were good pancakes and swore by his honour the
mustard was naught: now I'll stand to it, the
pancakes were naught and the mustard was good, and
yet was not the knight forsworn.
This is actually an amusing and instructive excerpt that is, in fact, explained a few lines further in the scene. Touchstone has entered the scene where Rosalind and Celia are engaged in a battle of wits over Nature's role as opposed to Fortunes role in life:
No? when Nature hath made a fair creature, may she
not by Fortune fall into the fire? Though Nature
hath given us wit to flout at Fortune, hath not
Fortune sent in this fool to cut off the argument?
Though changing the subject, Touchstone continues the mental gymnastics--exercise in wit--and talks about the oath he uses wherewith he swears "by mine honor ...": "No, by mine honour, but I was bid to come for you." He explains that if a person swears by something a person does not possess, then the oath sworn is not valid. As an example, he asks Celia and Rosalind to swear by their beards. Since they have no beards, and thus cannot truthfully swear anything by their beards, the oaths are both (1) no good and (2) not false oaths.
Touchstones explains further by saying (in prose, by the way, not poetry): "but if you swear by that that is not, you are not forsworn:". "Forsworn" means to go back (renounce) an oath or to swear falsely (commit perjury) or to deny an oath. What he means is that if you swear by what you don't have, then you cannot possibly swear falsely--you can swear by trickery, guile and deceit, but not falsely: you cannot be forsworn.
Now, back to the excerpt. Touchstone is telling about the incident during which he learned the oath, "by mine honor." He tells of a knight who swore "by his honor" about the tastiness of pancakes and mustard. Touchstone, it turns out, had a different opinion of the pancakes and mustard so was accusing the knight of deception--however--he excuses the knight of the accusation by saying, in a paraphrase, "Well, he swore by his honor and he apparently has no honor, so I must forgive him for falsifying his oath because his oath was no good anyway--he has no honor by which to swear."
As an aside, you can see how Shakespeare's use of rhetorical word schemes allows him to say the same thing I just said so much more brilliantly and succinctly than I have done in my paraphrase.