Narrated `Aisha: The people used to fast on 'Ashura (the tenth day of the month of Muharram) before the fasting of Ramadan was made obligatory. And on that day the Ka`ba used to be covered with a cover. When Allah made the fasting of the month of Ramadan compulsory, Allah's Apostle said, "Whoever wishes to fast (on the day of 'Ashura') may do so; and whoever wishes to leave it can do so."
Hadith Referenceصحيح البخاري / كتاب الحج / 1592
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة
Narrated Abu Sa`id Al-Khudri: The Prophet said "The people will continue performing the Hajj and `Umra to the Ka`ba even after the appearance of Gog and Magog." Narrated Shu`ba extra: The Hour (Day of Judgment) will not be established till the Hajj (to the Ka`ba) is abandoned.
Hadith Referenceصحيح البخاري / كتاب الحج / 1593
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة