Midrasch zu Wajikra 14:42

7) (Vayikra 14:42) ("And they shall take other stones, and they shall bring [them] in place of the stones; and he shall take other mortar and he shall plaster the house.") From here they ruled that no fewer than two stones are taken and no fewer than two stones are brought. And he does not bring one in place of two or two in place of one. But he may bring two in place of two, three, or four, and four in place of three or two.

8) "and they shall take … stones": I might think he could take stones from one side and bring them to the other side; it is, therefore, written "other (stones"). If (only) "other" (were written), I might think even roof-tiles or bricks; it is, therefore, written "stones." If both verses were not written, we would not know the halachah.

9) "and mortar" connotes all kinds: even bricks, even ordure, even clay-ground. I might think that he could take mortar from one side and bring it to the other side; it is, therefore, written "other (mortar"). If (only) "other" (were written), I might think even lime or gypsum; it is, therefore, written "afar" (lit., "earth"). If both verses were not written, we would not know the halachah....