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:20761Abū ʿAbdullāh al-Ḥāfiẓ > ʿAbdullāh b. Muḥammad b. Mūsá al-Ṣaydalānī > Muḥammad b. Ayyūb > Abū al-Walīd > Mahdī b. Maymūn > Ghaylān > Anas

[Machine] Indeed, you used to perform deeds that were more important in your eyes than hair, even though we used to consider them (i.e., such deeds) as destructive acts during the time of the Messenger of Allah (peace and blessings be upon him).  

البيهقي:٢٠٧٦١أَخْبَرَنَا أَبُو عَبْدِ اللهِ الْحَافِظُ أَخْبَرَنِي عَبْدُ اللهِ بْنُ مُحَمَّدِ بْنِ مُوسَى الصَّيْدَلَانِيُّ ثنا مُحَمَّدُ بْنُ أَيُّوبَ أنبأ أَبُو الْوَلِيدِ ثنا مَهْدِيُّ بْنُ مَيْمُونٍ ثنا غَيْلَانُ عَنْ أَنَسٍ قَالَ

إِنَّكُمْ لَتَعْمَلُونَ أَعْمَالًا هِيَ أَدَقُّ فِي أَعْيُنِكُمْ مِنَ الشَّعْرِ إِنْ كُنَّا لَنَعُدُّ عَلَى عَهْدِ رَسُولِ اللهِ ﷺ أَنَّهَا لَهِيَ الْمُوبِقَاتُ  

رَوَاهُ الْبُخَارِيُّ فِي الصَّحِيحِ عَنْ أَبِي الْوَلِيدِ

See similar narrations below:

Collected by Bukhārī, Aḥmad, Aḥmad's Zuhd

The Ṣaḥābah did not trivialize sins at the time of the Prophet ﷺ

bukhari:6492Abū al-Walīd > Mahdī > Ghaylān > Anas

Anas said, "You all do ˹bad˺ deeds which seem insignificant in your eyes, like hair, while we used to consider those ˹deeds˺ as destructive during the life-time of the Prophet ﷺ."  

Abū ʿAbdullāh said that ˹mūbiqāt˺ means muhlikāt (destructive actions)
البخاري:٦٤٩٢حَدَّثَنَا أَبُو الْوَلِيدِ حَدَّثَنَا مَهْدِيٌّ عَنْ غَيْلاَنَ عَنْ أَنَسٍ ؓ

قَالَ: إِنَّكُمْ لَتَعْمَلُونَ أَعْمَالاً هِيَ أَدَقُّ فِي أَعْيُنِكُمْ مِنَ الشَّعَرِ إِنْ كُنَّا نَعُدُّهَا عَلَى عَهْدِ النَّبِيِّ ﷺ الْمُوبِقَاتِ۔  

قَالَ أَبُو عَبْدِ اللَّهِ يَعْنِي بِذَلِكَ الْمُهْلِكَاتِ
ahmad:12604Yaḥyá b. Isḥāq > Mahdī > Ghaylān b. Jarīr > Anas b. Mālik

[Machine] Indeed, you are doing actions that are more delicate in your eyes than [strands of] hair, if we were to count them according to the scale of the Messenger of Allah ﷺ from the sinful deeds.  

أحمد:١٢٦٠٤حَدَّثَنَا يَحْيَى بْنُ إِسْحَاقَ حَدَّثَنَا مَهْدِيٌّ حَدَّثَنِي غَيْلَانُ بْنُ جَرِيرٍ عَنْ أَنَسِ بْنِ مَالِكٍ قَالَ

إِنَّكُمْ لَتَعْمَلُونَ أَعْمَالًا هِيَ أَدَقُّ فِي أَعْيُنِكُمْ مِنَ الشَّعْرِ إِنْ كُنَّا لَنَعُدُّهَا عَلَى عَهْدِ رَسُولِ اللهِ ﷺ مِنَ الْمُوبِقَاتِ  

ahmad:10995ʿAbd al-Malik b. ʿAmr > ʿAbbād / Ibn Rāshidʿan Dāwud b. Abū Hind > Abū Naḍrah > Abū Saʿīd

[Machine] "Indeed, you used to do deeds that were more precious in your eyes than hair. We used to count them during the time of the Messenger of Allah ﷺ among the calamities."  

أحمد:١٠٩٩٥حَدَّثَنَا عَبْدُ الْمَلِكِ بْنُ عَمْرٍو حَدَّثَنَا عَبَّادٌ يَعْنِي ابْنَ رَاشِدٍعَنْ دَاوُدَ بْنِ أَبِي هِنْدٍ عَنْ أَبِي نَضْرَةَ عَنْ أَبِي سَعِيدٍ قَالَ

إِنَّكُمْ لَتَعْمَلُونَ أَعْمَالًا لَهِيَ أَدَقُّ فِي أَعْيُنِكُمْ مِنَ الشَّعْرِ كُنَّا نَعُدُّهَا عَلَى عَهْدِ رَسُولِ اللهِ ﷺ مِنَ الْمُوبِقَاتِ  

ahmad:20751Hāshim b. al-Qāsim > Sulaymān > Ḥumayd b. Hilāl > Abū Qatādah > ʿUbādah b. Qurṭ or Qurṣ

[Machine] "You perform actions that are more important to you than hair, even if we were to count them as sins during the time of the Prophet ﷺ ."  

أحمد:٢٠٧٥١حَدَّثَنَا هَاشِمُ بْنُ الْقَاسِمِ حَدَّثَنَا سُلَيْمَانُ عَنْ حُمَيْدِ بْنِ هِلَالٍ عَنْ أَبِي قَتَادَةَ عَنْ عُبَادَةَ بْنِ قُرْطٍ أَوْ قُرْصٍ قَالَ

إِنَّكُمْ تَعْمَلُونَ أَعْمَالًا هِيَ أَدَقُّ فِي أَعْيُنِكُمْ مِنَ الشَّعْرِ إِنْ كُنَّا لَنَعُدُّهَا عَلَى عَهْدِ النَّبِيِّ ﷺ مِنَ الْمُوبِقَاتِ  

ahmad-zuhd:1084ʿAbdullāh from my father > ʿAbd al-Malik b. ʿAmr > ʿAbbād b. Rāshid > Dāwud b. Abū Hind > Abū Naḍrah > Abū Saʿīd al-Khudrī ؒ

Anas said "You people do (bad) deeds (commit sins) which seem in your eyes as tiny (minute) than hair while we used to consider those (very deeds) during the life-time of the Prophet ﷺ as destructive sins." (Using translation from Bukhārī 6492)   

الزهد لأحمد:١٠٨٤حَدَّثَنَا عَبْدُ اللَّهِ حَدَّثَنَا أَبِي حَدَّثَنَا عَبْدُ الْمَلِكِ بْنُ عَمْرٍو حَدَّثَنَا عَبَّادُ بْنُ رَاشِدٍ عَنْ دَاوُدَ بْنِ أَبِي هِنْدَ عَنْ أَبِي نَضْرَةَ عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ رَحِمَهُ اللَّهُ قَالَ

إِنَّكُمْ لَتَعْمَلُونَ أَعْمَالًا هِيَ أَدَقُّ فِي أَعْيُنِكُمْ مِنَ الشَّعْرِ كُنَّا نَعُدُّهَا عَلَى عَهْدِ رَسُولِ اللَّهِ ﷺ مِنَ الْمُوبِقَاتِ