A3, S1, l. 69-75 Any idea?

[Eva Marina]

"If ‘t be so, for Banquo’s issue have I filed in my mind; for them the gracious Duncan have I murdered, put rancors in the vessel of my peace only for them, and mine eternal jewel given the common enemy of man to make them kings, the seeds of Banquo kings." --Macbeth, Act 3, Scene 1, line 69-75

Does anyone know what this means? I have a vague (very vague!) idea, but I have no idea how to go about analyzing it, as we are supposed to for my English class. I've come across "issue" a few times in the play, but does anyone know what it means?
Any help is greatly appreciated!

[Virgil]

"Issue" here refers to the sense of coming forth. What MacBeth is lamenting is that the witches have predicted he will be king but also that Banquo's descendants will ultimately have the thrown and dynasty. MacBeth then feels that he has done all his evil deeds for the benefit of someone else and he will try to alter the prophesy. Shakespeare will have a key word for a play and "issue" may be the key word for MacBeth. I would have to re-read the play to confirm that. For your class I would read in a good dictionary all the nuances of "issue" and see how they fit the play. You might have the makings of a very good essay/paper. Let me know how it turns out.