Sahih al-Bukhari, Volume 4, Book 52, Hadith 128 (USC-MSA) ⓘ
Narrated `Aisha: the mother of the faithful believers: The Prophet was asked by his wives about the Jihad and he replied, "The best Jihad (for you) is (the performance of) Hajj."
حَدَّثَنَا قَبِيصَةُ، حَدَّثَنَا سُفْيَانُ، عَنْ مُعَاوِيَةَ، بِهَذَا. وَعَنْ حَبِيبِ بْنِ أَبِي عَمْرَةَ، عَنْ عَائِشَةَ بِنْتِ طَلْحَةَ، عَنْ عَائِشَةَ أُمِّ الْمُؤْمِنِينَ، عَنِ النَّبِيِّ صلى الله عليه وسلم سَأَلَهُ نِسَاؤُهُ عَنِ الْجِهَادِ فَقَالَ " نِعْمَ الْجِهَادُ الْحَجُّ " .
also referenced under: Book 56, Hadith 92 (In-Book) & Hadith 2876 (DarusSalam)