Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
bayhaqi:9668ʿAlī b. Aḥmad b. ʿAbdān > Aḥmad b. ʿUbayd al-Ṣaffār > Yaḥyá b. Muḥammad al-Ḥinnāʾī > Shaybān > Ḥammād b. Salamah > Sulaymān al-Taymī > Abū Mijlaz > a man Saʾal Ibn ʿUmar > Innī

[Machine] "I threw the pebble without knowing if I threw it six or seven times. He said, 'Go to that man, he wants Ali.' (Ali) went to him and asked him about it. He said, 'If I had done something wrong in my prayer, I would have repeated it.' So he came back and informed him (the Imam) about it. The sheikh said, 'Abu al-Hasan (Ali) is truthful.' The sheikh said, 'And it seems that he intends, and Allah knows best, to repeat the suspicious act. Similarly, in stoning, one should repeat the act if there is doubt about it. It has been mentioned in the book of prayer, the hadith of Abu Sa'id and others, narrating from the Prophet ﷺ regarding building on certainty. And success is from Allah.'"

Note: the passage is a hadith, a saying or action of Prophet Muhammad, and it discusses the act of stoning during Hajj rituals. Some terms, names, and phrases have been transliterated.  

البيهقي:٩٦٦٨أَخْبَرَنَا عَلِيُّ بْنُ أَحْمَدَ بْنِ عَبْدَانَ أنبأ أَحْمَدُ بْنُ عُبَيْدٍ الصَّفَّارُ ثنا يَحْيَى بْنُ مُحَمَّدٍ الْحِنَّائِيُّ ثنا شَيْبَانُ ثنا حَمَّادُ بْنُ سَلَمَةَ ثنا سُلَيْمَانُ التَّيْمِيُّ عَنْ أَبِي مِجْلَزٍ أَنَّ رَجُلًا سَأَلَ ابْنَ عُمَرَ فَقَالَ

إِنِّي رَمَيْتُ الْجَمْرَةَ وَلَمْ أَدْرِ رَمَيْتُ سِتًّا أَوْ سَبْعًا قَالَ ائْتِ ذَاكَ الرَّجُلَ يُرِيدُ عَلِيًّا ؓ فَذَهَبَ فَسَأَلَهُ فَقَالَ أَمَّا أَنَا لَوْ فَعَلْتُ فِي صَلَاتِي لَأَعَدْتُ الصَّلَاةَ فَجَاءَ فَأَخْبَرَهُ بِذَلِكَ فَقَالَ صَدَقَ أَبُو الْحَسَنِ قَالَ الشَّيْخُ وَكَأَنَّهُ أَرَادَ وَاللهُ أَعْلَمُ لَأَعَدْتُ الْمَشْكُوكَ فِي فِعْلِهِ كَذَلِكَ فِي الرَّمْيِ يُعِيدُ الْمَشْكُوكَ فِي رَمْيِهِ وَقَدْ مَضَى فِي كِتَابِ الصَّلَاةِ حَدِيثُ أَبِي سَعِيدٍ وَغَيْرِهِ عَنِ النَّبِيِّ ﷺ فِي الْبِنَاءِ عَلَى الْيَقِينِ وَبِاللهُ التَّوْفِيقُ