(18) باب مَنْ قَالَ إِنَّ الإِيمَانَ هُوَ الْعَمَلُ
Narrated Abu Huraira:
Allah's Messenger (ﷺ) was asked, "What is the best deed?" He replied, "To believe in Allah and His Apostle (Muhammad). The questioner then asked, "What is the next (in goodness)? He replied, "To participate inJihad (religious fighting) in Allah's Cause." The questioner again asked, "What is the next (in goodness)?" He replied, "To perform Hajj (Pilgrim age to Mecca) 'Mubrur, (which is accepted by Allah and is performed with the intention of seeking Allah's pleasure only and not to show off and without committing a sin and in accordance with the traditions of the Prophet)."
Reference: Sahih al-Bukhari 26
In-book reference: Book 2, Hadith 19
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 2, Hadith 26