Abu Dharr (May Allah be pleased with him) reported:
The Messenger of Allah ﷺ was asked: "Which deed is the best?" He ﷺ replied, "Faith in Allah and Jihad (fighting, struggle) in the Cause of Allah."

[Al-Bukhari and Muslim].

وعن أبي ذر رضي الله عنه قال: قلت يا رسول الله أي العمل أفضل؟ قال: "الإيمان بالله والجهاد في سبيله" ((متفق عليه))