Du'a of Istikhara

اللَّهُمَّ إِنِّي أَسْتَخِيرُكَ بِعِلْمِكَ، وَأَسْتَقْدِرُكَ بِقُدْرَتِكَ، وَأَسْأَلُكَ مِنْ فَضْلِكَ الْعَظِيمِ، فَإِنَّكَ تَقْدِرُ وَلَا أَقْدِرُ، وَتَعْلَمُ وَلَا أَعْلَمُ، وَأَنْتَ عَلَّامُ الْغُيُوبِ. اللَّهُمَّ إِنْ كُنْتَ تَعْلَمُ أَنَّ هَذَا الْأَمْرَ خَيْرٌ لِي فِي دِينِي وَمَعَاشِي وَعَاقِبَةِ أَمْرِي فَاقْدُرْهُ لِي وَيَسِّرْهُ لِي ثُمَّ بَارِكْ لِي فِيهِ، وَإِنْ كُنْتَ تَعْلَمُ أَنَّ هَذَا الْأَمْرَ شَرٌّ لِي فِي دِينِي وَمَعَاشِي وَعَاقِبَةِ أَمْرِي فَاصْرِفْهُ عَنِّي وَاصْرِفْنِي عَنْهُ، وَاقْدُرْ لِيَ الْخَيْرَ حَيْثُ كَانَ ثُمَّ أَرْضِنِي بِهِ

Allahumma inni astakhiruka bi'ilmik, wa astaqdiruka biqudratik, wa as'aluka min fadlikal-'azim. Fa innaka taqdiru wa la aqdir, wa ta'lamu wa la a'lam, wa anta 'allamul-ghuyub. Allahumma in kunta ta'lamu anna hadhal-amra khayrun li fi dini wa ma'ashi wa 'aqibati amri faqdurhu li wa yassirhu li thumma barik li fih. Wa in kunta ta'lamu anna hadhal-amra sharrun li fi dini wa ma'ashi wa 'aqibati amri fasrifhu 'anni wasrifni 'anh, waqdur liyal-khayra haythu kana thumma ardini bih.

“O Allah, I seek Your guidance by Your knowledge, and I seek Your power by Your power, and I ask You of Your immense bounty — for You have power and I have none, You know and I do not, and You are the Knower of all that is hidden. O Allah, if You know that this matter is good for me in my religion, my livelihood, and the outcome of my affair, then decree it for me, make it easy for me, and bless me in it. And if You know that this matter is bad for me in my religion, my livelihood, and the outcome of my affair, then turn it away from me and turn me away from it, and decree for me what is good wherever it may be, then make me content with it.”

Said after praying two rak'ahs outside the obligatory prayers, when weighing a decision. At the point of 'this matter', the person names the matter.

Source: Bukhari 1162