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:20738Abū Saʿīd

[Machine] The passage is in Arabic and its translation into English is as follows:

"Omar, may Allah be pleased with him, said: For those against whom you make a claim (i.e., a financial claim) by swearing, [saying, 'It is my right] fifty times what he could swear by. They refused and were embarrassed by swearing so he (Omar) said to the others, "You swear," but they refused. Abu Sa'id added I, with my chain of authority, confirm that Shafi'i said, 'Allah's Messenger ﷺ had taken the oath of allegiance from the Ansar on the Day (of the pledge at Hudaybiyah). And he said to them, 'This is the allegiance of you the Ansar concerning the matter which involves me and you.' And then the Prophet ﷺ held out his hand, and then they (i.e., the Ansar) were reluctant to offer their hands. Then the Prophet ﷺ said [to them), 'Offer your hands.' Then they offered their hands and the Prophet ﷺ said, 'I take the oath of allegiance from you for Islam and emigration (to Medina), and what involves you in me.' So wherever the Prophet ﷺ took the oath of allegiance from anyone of the believing women, he used to say to her, 'I have taken your pledge of allegiance for Islam' (and emigration). Abu Sa'id was asked by one of his companions, 'Did the Prophet ﷺ take the oath of allegiance from you?' He replied, 'Yes.'"

Please note that due to the translation from Arabic to English, the meaning may slightly differ.  

البيهقي:٢٠٧٣٨أَخْبَرَنَا أَبُو سَعِيدِ بْنُ أَبِي عَمْرٍو فِي آخَرِينَ قَالُوا ثنا أَبُو الْعَبَّاسِ مُحَمَّدُ بْنُ يَعْقُوبَ أنبأ الرَّبِيعُ بْنُ سُلَيْمَانَ أنبأ الشَّافِعِيُّ أنبأ مَالِكُ بْنُ أَنَسٍ عَنِ ابْنِ شِهَابٍ عَنْ سُلَيْمَانَ بْنِ يَسَارٍ أَنَّ رَجُلًا مِنْ بَنِي سَعْدِ بْنِ لَيْثٍ أَجْرَى فَرَسًا فَوَطِئَ عَلَى إِصْبَعِ رَجُلٍ مِنْ جُهَيْنَةَ فَنَزَّى مِنْهَا فَمَاتَ فَقَالَ

عُمَرُ ؓ لِلَّذِينَ ادُّعِيَ عَلَيْهِمْ تَحْلِفُونَ خَمْسِينَ يَمِينًا مَا مَاتَ مِنْهَا؟ فَأَبَوْا وَتَحَرَّجُوا مِنَ الْأَيْمَانِ فَقَالَ لِلْآخَرِينَ احْلِفُوا أَنْتُمْ فَأَبَوْا زَادَ أَبُو سَعِيدٍ فِي رِوَايَتِهِ بِإِسْنَادِهِ قَالَ قَالَ الشَّافِعِيُّ رَحِمَهُ اللهُ فَقَدْ رَأَى رَسُولُ اللهِ ﷺ الْيَمِينَ عَلَى الْأَنْصَارِيِّينِ يَسْتَحِقُّونَ فَلَمَّا لَمْ يَحْلِفُوا حَوَّلَهَا عَلَى الْيَهُودِ يُبَرَّءُونَ بِهَا وَرَأَى عُمَرُ ؓ الْيَمِينَ عَلَى اللَّيْثِيِّينَ يُبَرَّءُونَ بِهَا فَلَمَّا أَبَوْا حَوَّلَهَا عَلَى الْجُهَنِيِّينَ يَسْتَحِقُّونَ بِهَا فَكُلُّ هَذَا تَحْوِيلُ يَمِينٍ مِنْ مَوْضِعٍ قَدْ رُتِّبَتْ فِيهِ إِلَى الْمَوْضِعِ الَّذِي يُخَالِفُهُ فَبِهَذَا وَمَا أَدْرَكْنَا عَلَيْهِ أَهْلَ الْعِلْمِ بِبَلَدِنَا يَحْكُونَ عَنْ مُفْتِيهِمْ وَحُكَّامِهِمْ قَدِيمًا وَحَدِيثًا قُلْنَا فِي رَدِّ الْيَمِينِ