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.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
nasai-kubra:6428 – Qutaybah b. Saʿīd > Sufyān > Hishām b. ʿUrwah from his father > Ibn ʿAbbās > Law Ghaḍ al-Nās > al-Rubuʿ

"If the people were to reduce (their bequests) to one-quarter (of their wealth, that would be better), because the Messenger of Allah said: 'One-third, and one-third is much or large.'" (Using translation from Nasāʾī 3634)  

الكبرى للنسائي:٦٤٢٨ – أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ قَالَ حَدَّثَنَا سُفْيَانُ عَنْ هِشَامِ بْنِ عُرْوَةَ عَنْ أَبِيهِ عَنِ ابْنِ عَبَّاسٍ قَالَ لَوْ غَضَّ النَّاسُ إِلَى الرُّبُعِ؛

لَأَنَّ رَسُولَ اللهِ ﷺ قَالَ «الثُّلُثُ وَالثُّلُثُ كَثِيرٌ أَوْ كَبِيرٌ»  

See similar narrations below:

Collected by Bukhārī, Nasāʾī, Ibn Mājah, Aḥmad, Suyūṭī
bukhari:2743 – Qutaybah b. Saʿīd > Sufyān > Hishām b. ʿUrwah from his father > Ibn ʿAbbās > Law Ghaḍ al-Nās > al-Rubʿ Lʾan

I recommend that people reduce the proportion of what they bequeath by will to the fourth (of the whole legacy), for Messenger of Allah ﷺ said, "One-third, yet even one third is too much."  

البخاري:٢٧٤٣ – حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ حَدَّثَنَا سُفْيَانُ عَنْ هِشَامِ بْنِ عُرْوَةَ عَنْ أَبِيهِ عَنِ ابْنِ عَبَّاسٍ ؓ قَالَ

لَوْ غَضَّ النَّاسُ إِلَى الرُّبْعِ لأَنَّ رَسُولَ اللَّهِ ﷺ قَالَ: «الثُّلُثُ، وَالثُّلُثُ كَثِيرٌ۔» أَوْ «كَبِيرٌ۔»  

nasai:3634 – Qutaybah b. Saʿīd > Sufyān > Hishām b. ʿUrwah from his father > Ibn ʿAbbās > Law Ghaḍ al-Nās > al-Rubuʿ

"If the people were to reduce (their bequests) to one-quarter (of their wealth, that would be better), because the Messenger of Allah said: 'One-third, and one-third is much or large.'"  

النسائي:٣٦٣٤ – أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ قَالَ حَدَّثَنَا سُفْيَانُ عَنْ هِشَامِ بْنِ عُرْوَةَ عَنْ أَبِيهِ عَنِ ابْنِ عَبَّاسٍ قَالَ لَوْ غَضَّ النَّاسُ إِلَى الرُّبُعِ

لأَنَّ رَسُولَ اللَّهِ ﷺ قَالَ الثُّلُثَ وَالثُّلُثُ كَثِيرٌ أَوْ كَبِيرٌ  

ibnmajah:2711 – ʿAlī b. Muḥammad > Wakīʿ > Hishām b. ʿUrwah from his father > Ibn ʿAbbās > Wadidt > al-Nās Ghaḍḍūā from al-Thuluth > al-Rubuʿ

“I would like the people to reduce (the will) from one third to one quarter, because the Messenger of Allah ﷺ said: 'One third is a lot.'”  

ابن ماجة:٢٧١١ – حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ حَدَّثَنَا وَكِيعٌ عَنْ هِشَامِ بْنِ عُرْوَةَ عَنْ أَبِيهِ عَنِ ابْنِ عَبَّاسٍ قَالَ وَدِدْتُ

أَنَّ النَّاسَ غَضُّوا مِنَ الثُّلُثِ إِلَى الرُّبُعِ لأَنَّ رَسُولَ اللَّهِ ﷺ قَالَ الثُّلُثُ كَبِيرٌ أَوْ كَثِيرٌ  

ahmad:2076 – Wakīʿ > Hishām from his father > Ibn ʿAbbās > Wadidt

“I would like the people to reduce (the will) from one third to one quarter, because the Messenger of Allah ﷺ said: 'One third is a lot.'” (Using translation from Ibn Mājah 2711)   

أحمد:٢٠٧٦ – حَدَّثَنَا وَكِيعٌ حَدَّثَنَا هِشَامٌ عَنْ أَبِيهِ عَنِ ابْنِ عَبَّاسٍ قَالَ وَدِدْتُ

أَنَّ النَّاسَ غَضُّوا مِنَ الثُّلُثِ إِلَى الرُّبُعِ فِي الْوَصِيَّةِ لِأَنَّ النَّبِيَّ ﷺ قَالَ الثُّلُثُ كَثِيرٌ أَوْ كَبِيرٌ