Halakhah do Ezechiela 36:13

3. On the third Sabbath, which is the fifteenth of Adar, we skip, and on the fourth Sabbath which is the twenty-second of Adar we take out two [Torah] scrolls — in one [the Reader] reads the weekly portion, and in the second he reads the Portion of the [Red] Heifer [Numbers 1–22], and the haftarah is "I shall sprinkle upon you pure waters..." [Ezekiel 36:13–36]. (And see above Section 137 Paragraph 5.)