Muhammad ibn Ali ibn Mahbub, from Ahmad ibn Muhammad, from Ibn Abi Najran, from Hammad ibn Isa, from Hariz, from Zurarah and Ibn Muslim, who said: We said to Abu Ja’far عليه السلام, peace be upon him: “A man prayed four (rak‘ahs) while traveling (full prayer), Should he repeat it or not?” Imam عليه السلام said: “If the verse of shortening (‘ayat al-taqsir’) was recited to him and it was explained to him, then he prayed four (rak‘ahs), he must repeat (the prayer). But if it had not been recited to him and he did not know it, then there is no repetition upon him.”