Ibn Abbas reported: The Prophet, peace and blessings be upon him, said, “No good deeds are better than what is done in these first ten days of Dhul-Hijjah.” Some companions of the Prophet said, “Not even jihad in the way of Allah?” The Prophet said, “Not even jihad in the way of Allah, except for a man who goes out with his life and wealth at risk and he returns with nothing.”

Source: Ṣaḥīḥ al-Bukhārī 969

Grade: Sahih (authentic) according to Al-Bukhari

عَنْ ابْنِ عَبَّاسٍ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ قَالَ مَا الْعَمَلُ فِي أَيَّامٍ أَفْضَلَ مِنْهَا فِي هَذِهِ يعني أيام العشر قَالُوا وَلَا الْجِهَادُ قَالَ وَلَا الْجِهَادُ إِلَّا رَجُلٌ خَرَجَ يُخَاطِرُ بِنَفْسِهِ وَمَالِهِ فَلَمْ يَرْجِعْ بِشَيْءٍ 

969 صحيح البخاري كتاب العيدين باب فضل العمل في أيام التشريق