Al-Kāfi - Volume 3 > The Time of Salah (Prayer) In a Cloudy Day, Windy and One Who Has Performed Salah (Prayer) Without Facing the Direction of Qiblah
Hadith #7

7ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ حَمَّادٍ عَنْ حَرِيزٍ عَنْ زُرَارَةَ قَالَ قَالَ أَبُو جَعْفَرٍ (عَلَيْهِ الْسَّلام) يُجْزِئُ التَّحَرِّي أَبَداً إِذَا لَمْ يُعْلَمْ أَيْنَ وَجْهُ الْقِبْلَةِ.

7. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Hammad from Flariz from Zurarah who has said the following: “Abu Ja‘far, ‘Alayhi al-Salam, has said, ‘Al-Taharriy (investigation) is always sufficient in the issue of finding al-Qiblah (al-Ka‘bah).’”