Bikkurim 1:2, with my somewhat rough translation:
האריסין והחכורות והסקריקון והגזלן אין מביאים מאותו הטעם משום שנאמר ראשית ביכורי אדמתך
Sharecroppers, muggers,1 and thieves do not bring Bikkurim [from the sharecropped or stolen land] for this same reason - because the verse [in Shemos 23] says, “The first fruits of the land.”
1 - I’m not sure of a more accurate word in English for סקריקון. Bartenura translates it as one who threatens to kill people if they don’t give him their land.
We have a general principle called Mitzvah HaBa’ah BeAveirah - a mitzvah performed by violating an aveirah - which is rejected (Sukkah 30a et. al.). Now, a thief is in violation of Lo Sasig, the prohibition against stealing land (see Rashi to Devarim 19:14, quoting Sifrei there), and the mugger is in violation of Lo Sachmod, the prohibition against coveting (see BM 5b). So why do we need to derive these cases from Shemos 23, when even had the passuk not been written we would have forbidden such Bikkurim?
Granted, the passuk would have to have been written for the other cases in the Mishnah (sharecroppers, plus the various cases from Mishnah 1). My question is on the wording “they don’t bring for this reason” - implying that they don’t bring only because of this reason. This isn’t true by muggers and thieves - they can’t bring for other reasons, either!