It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) used to touch (istilam) the Yemeni Corner and the Black Stone, and did not touch any corner other than these two.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13512