Ibn Majah 1164

Its isnad is sahih. Ahmad (6/30) narrated it from Hushaym, who said, "Khalid told us," transmitted at length in this manner. Muslim also narrated it in the Book of the Prayer of the Traveler, Chapter on the Permissibility of Voluntary Prayer While Standing or Sitting... etc., no. 730, from the hadith of Hushaym, transmitted similarly at length.