From Sahih Bukhari (Hadith 1519):
Narrated Abu Huraira:The Prophet (ﷺ) was asked, "Which is the best deed?" He said, "To believe in Allah and His Apostle." He was then asked, "Which is the next (in goodness)?" He said, "To participate in Jihad in Allah's Cause." He was then asked, "Which is the next?" He said, "To perform Hajj-Mabrur
Reference: Bukhari 1519