[1423] One who develops the "I shall come to know the unknown" faculty (anaññātaññassāmītindriya) — will that one realize the perfect-knower faculty (aññātāvindriya)?
Yes.
Or, one who will realize the perfect-knower faculty — does that one develop the "I shall come to know the unknown" faculty?
Seven persons will realize the perfect-knower faculty, but they do not develop the "I shall come to know the unknown" faculty; the eighth person (aṭṭhamaka) will realize the perfect-knower faculty and also develops the "I shall come to know the unknown" faculty.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.