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.
ibnmajah:4204ʿAbdullāh b. Saʿīd > Abū Khālid al-Aḥmar > Kathīr b. Zayd > Rubayḥ b. ʿAbd al-Raḥman b. Abū Saʿīd al-Khudrī from his father > Abū Saʿīd

“The Messenger of Allah ﷺ came out to us when we were discussing Dajjal (False Christ) and said: ‘Shall I not tell you of that which I fear more for you than Dajjal?’ We said: ‘Yes.’ He said: ‘Hidden polytheism, when a man stands to pray and makes it look good because he sees a man looking at him.’”  

ابن ماجة:٤٢٠٤حَدَّثَنَا عَبْدُ اللَّهِ بْنُ سَعِيدٍ حَدَّثَنَا أَبُو خَالِدٍ الأَحْمَرُ عَنْ كَثِيرِ بْنِ زَيْدٍ عَنْ رُبَيْحِ بْنِ عَبْدِ الرَّحْمَنِ بْنِ أَبِي سَعِيدٍ الْخُدْرِيِّ عَنْ أَبِيهِ عَنْ أَبِي سَعِيدٍ قَالَ

خَرَجَ عَلَيْنَا رَسُولُ اللَّهِ ﷺ وَنَحْنُ نَتَذَاكَرُ الْمَسِيحَ الدَّجَّالَ فَقَالَ أَلاَ أُخْبِرُكُمْ بِمَا هُوَ أَخْوَفُ عَلَيْكُمْ عِنْدِي مِنَ الْمَسِيحِ الدَّجَّالِ قَالَ قُلْنَا بَلَى فَقَالَ الشِّرْكُ الْخَفِيُّ أَنْ يَقُومَ الرَّجُلُ يُصَلِّي فَيُزَيِّنُ صَلاَتَهُ لِمَا يَرَى مِنْ نَظَرِ رَجُلٍ  


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Collected by Suyūṭī
suyuti:8973a
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السيوطي:٨٩٧٣a

"أَلا أُخبركم بما هو أَخوف عليكم عندى من المسيح الدجَّال؟ الشِّرك الخفىُّ أَن يقوم الرَّجل فيصلى فَيُزَيِّنُ صلاته لما يرى من نظر رجلٍ ".  

[هـ] ابن ماجة عن أَبى سعيد