Al-Kāfi - The Book of Prayer

Chapter: Salah (prayer) for Istikharah (asking Allah to Choose for One What Is Good) َّدٍ رَفَعَهُ عَنْهُ٠) أَنَّهُ قَالَ لِبَعْضِ أَصْحَابِهِ وَقَدْ سَأَلَهُ عَنِ الأ٠ْضِي فِيهِ وَلاَ يَجِدُ أَحَداً يُشَاوِرُهُ فَكَيْفَ يَصْنَعُ قَالَ شَاوِرْ رَبَّكَ قَالَ فَقَالَ لَهُ كَيْفَ قَالَ لَهُ انْوِ الْحَاجَةَ فِي نَفْسِكَ ثُ٠َّ اكْتُبْ رُقْعَتَيْنِ فِي وَاحِدَةٍ لاَ وَفِي وَاحِدَةٍ نَعَ٠َا فِي بُنْدُقَتَيْنِ ٠َّ صَلِّ رَكْعَتَيْنِ وَاجْعَلْهُ٠َا تَحْتَ ذَيْلِكَ وَقُلْ يَا الله إِنِّي أُشَاوِرُكَ فِي أَ٠ْرِي هَذَا وَأَنْتَ خَيْرُ ٠ُشِيرٍ فَأَشِرْ عَلَيَّ بِ٠َا فِيهِ صَلاَحٌ وَحُسْنُ عَاقِبَةٍ ثُ٠َّ أَدْخِلْ يَدَكَ فَإِنْ كَانَ فِيهَا نَعَ٠ْ فَافْعَلْ وَإِنْ كَانَ فِيهَا لاَ لاَ تَفْعَلْ هَكَذَا شَاوِرْ رَبَّكَ.

Place them inside two balls of clay, perform two Rak‘at Salah (prayer) and place them under your furnishing and say, “O Allah, I consult You in this matter and You are the best consultant and advisor. Grant me a sign about that which is beneficial and is of good consequences,” then take out one of the papers; if it is “yes”, then do what you wanted and if it is “no” then do not do it.

This is how you consult your Lord.’” رفوع - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (15/454))