Al-Hujjah must appear

“If there are no people on the earth except two men, one of them must be al-Hujjah (Imam al-Mahdi).”

“If only two men remain on the earth, one of them will be the Hujjah over the other.” The same was narrated by Muhammad bin Ya’qoob from Muhammad bin al-Hasan from Sahl bin Ziyad from Muhammad bin Eessa.

“If people are just two men, one of them will be the imam. The last one to die is the imam lest someone protests against Allah that He has left him without an authority from Him.”

“If there are no people on the earth except two, one of them will be al-Hujjah.”

“If there are no people on the earth except two, one of them will the imam.”