Sa’ad, from Muhammad ibn al-Husayn, from Ali ibn al-Nu'man, from Suwayd al-Qalla, from Abu Ayyub, from Abu Basir, from Abu Abdillah عليه السلام, peace be upon him, who said: I asked Imam al-Sadiq عليه السلام about a man who forgets and prays four rak‘ahs while traveling. Imam عليه السلام said: “If he remembers during that day, then he should repeat (and shorten the prayer), And if he does not remember until that day has passed, then there is no repetition upon him.”