Musnad Ahmad Hadith 7820

It is narrated from Abu Huraira (may Allah be pleased with him) that once the Holy Prophet (ﷺ) led the Zuhr or Asr prayer and ended the prayer after only two rak'ahs. At this, the hasty people left and began to say that the number of rak'ahs in the prayer had been reduced. Meanwhile, Dhul-Yadain bin Abd Amr, who was an ally of Banu Zuhrah, submitted, "O Messenger of Allah! Did you forget or has the number of rak'ahs in the prayer been reduced?" The Holy Prophet (ﷺ) asked the companions (may Allah be pleased with them), "Is it as Dhul-Yadain is saying?" The companions (may Allah be pleased with them) confirmed it. Upon this, the Holy Prophet (ﷺ) performed the two rak'ahs that had been left out, then after saying salam, while sitting, performed two prostrations of forgetfulness (sajda sahw).