Abu Ash-Sha'tha said, "Who keeps away from some portion of the Ka'bah?" Mu'awiya used to touch the four corners of the Ka'bah, Ibn 'Abbas said to him, "These two corners (the one facing the Hijr) are not to be touched." Mu'awiya said, "Nothing is untouchable in the Ka'bah." And Ibn Az-Zubair used to touch all the corners of the Ka'bah

English translation · Sahih al-Bukhari