Narrated 'Ikrima:
Ibn 'Abbas said, "We stayed for 19 days with Prophet on a journey during which we used to offer shortened prayers." Ibn 'Abbas added, "We offer the Qasr prayer (i.e. shortened prayer) If we stay up...
O Allah, You alone do we worship and to You we pray and bow down prostrate. To You we hasten to worship and to serve. Our hope is for Your mercy and we fear Your punishment. Surely, Your punishment of the disbelievers...
-> Read More Info: Al-Bayhaqi graded its chain authentic in As-Sunan Al-Kubra. Al-Albani said in 'Irwa'ul-GhaliL 2/170 that its chain is authentic as a statement of 'Umar.