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How to Perfom Istikhāra

Istikhāra literally means "to seek that which is good" and is the third part of a 3-step decision making process:

1. Preparation - Use your own rationale and assess your circumstances. Do your own research.

2. Istishāra (seek advice) - Ask someone of experience and knowledge in the topic you're looking for guidance on

3. Istikhāra (seek goodness) - Maybe you've narrowed it down, but are conflicted in making your final decision. You want confidence and clarity, and this is where istikhāra finally comes into play

Method
Pray two rakaʿāt of voluntary prayer (any prayer outside the five obligatory ones) and recite any Surahs you'd like after Fatiha in each rakah as there are no Surahs specifed by The Prophet ﷺ. Once you finish - ie, you say your salām for the prayer - recite the duʿāʾ (prayer) of istikhāra in Arabic as recommended to us by the Prophet ﷺ and then explicitly state your need in any language you'd like. No extra duʿāʾ afterwards is required.

اللَّهُمَّ إِنِّي أَسْتَخِيرُكَ بِعِلْمِكَ وَأَسْتَقْدِرُكَ بِقُدْرَتِكَ، وَأَسْأَلُكَ مِنْ فَضْلِكَ الْعَظِيمِ، فَإِنَّكَ تَقْدِرُ وَلاَ أَقْدِرُ وَتَعْلَمُ وَلاَ أَعْلَمُ وَأَنْتَ عَلاَّمُ الْغُيُوبِ، اللَّهُمَّ إِنْ كُنْتَ تَعْلَمُ أَنَّ هَذَا الأَمْرَ ‭[mention decision here]‬ خَيْرٌ لِي فِي دِينِي وَمَعَاشِي وَعَاقِبَةِ أَمْرِي فَاقْدُرْهُ لِي وَيَسِّرْهُ لِي ثُمَّ بَارِكْ لِي فِيهِ، وَإِنْ كُنْتَ تَعْلَمُ أَنَّ هَذَا الأَمْرَ شَرٌّ لِي فِي دِينِي وَمَعَاشِي وَعَاقِبَةِ أَمْرِي فَاصْرِفْهُ عَنِّي وَاصْرِفْنِي عَنْهُ، وَاقْدُرْ لِي الْخَيْرَ حَيْثُ كَانَ ثُمَّ أَرْضِنِي بِهِ


Translation: "Oh Allah, I’m asking You for goodness through Your [Infinite] Knowledge, and I’m asking You for strength through Your Divine Ability, and I’m asking You from Your Infinite Grace. Because You’re completely able to do, while I simply cannot. You know everything, and I do not, and You know everything that’s unseen. Dear God, if You know that this decision [mention decision here] is good for me in terms of my religiosity, my worldly life, and afterlife, then decree it, facilitate it for me with ease, and bless me through it. But if You know that this has bad consequences on my religiosity, my worldly life, and afterlife, then get it away from me and get me away from it, and [instead of that] decree what’s better for me, whatever it may be, and make me content with it.

Outcome
You will NOT necessarily see a dream/vision/sign/etc. Allāh ﷻ will place a bit of inclination in your heart towards going through with the action or not.

Conclusion
Istikhāra is a natural process. Don't expect anything otherworldly. All istikhāra ensures is that you have the blessings of Allāh backing your choice. There is no istikhāra for Ḥarām actions (ex. Should I drink this alcohol?) or obligatory actions (ex. Should I pray ʿĪshāʾ today?). Do not regret your decision afterwards as doing so would be to regret and doubt in Allāh's guidance. Even if your decision "doesn't work out" how you envisioned, know that it was better for you and that there are blessings in it even if you can't see them yet.
Istikhara
Method