Abu Darda reported: The Prophet, peace and blessings be upon him, said, “Shall I not tell you of the best of your deeds, which is the purest to your King, which raises you among your ranks, which is better for you than spending gold and money in charity, and which is better for you than meeting your enemy and striking the necks of each other?” They said, “Of course!” The Prophet said, “It is the remembrance of Allah Almighty.”
Source: Sunan al-Tirmidhī 3377
Grade: Sahih (authentic) according to Al-Albani
عَنْ أَبِي الدَّرْدَاءِ قَالَ قَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَلَا أُنَبِّئُكُمْ بِخَيْرِ أَعْمَالِكُمْ وَأَزْكَاهَا عِنْدَ مَلِيكِكُمْ وَأَرْفَعِهَا فِي دَرَجَاتِكُمْ وَخَيْرٌ لَكُمْ مِنْ إِنْفَاقِ الذَّهَبِ وَالْوَرِقِ وَخَيْرٌ لَكُمْ مِنْ أَنْ تَلْقَوْا عَدُوَّكُمْ فَتَضْرِبُوا أَعْنَاقَهُمْ وَيَضْرِبُوا أَعْنَاقَكُمْ قَالُوا بَلَى قَالَ ذِكْرُ اللَّهِ تَعَالَى
3377 سنن الترمذي كتاب الدعوات باب منه
2629 المحدث الألباني خلاصة حكم المحدث صحيح في صحيح الجامع