Muwaththa' Malik · #462
حَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، قَالَ مَا بَيْنَ الْمَشْرِقِ وَالْمَغْرِبِ قِبْلَةٌ إِذَا تُوُجِّهَ قِبَلَ الْبَيْتِ .
English
Yahya related to me from Malik from Nafi that Umar ibn al-Khattab said, "Any direction that is between east and west can be taken as a qibla if the person praying is face-on to the House