Amr bin Shu'ayb narrates from his father, and he from his grandfather (may Allah be pleased with him), who said: I saw the Messenger of Allah (peace and blessings be upon him) pressing his face and his chest against the Multazam.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9765
Sayyiduna Ibn Abbas (may Allah be pleased with him) used to cling to the place between the Corner and the Door, and he used to say: Whoever clings to the place between the Corner and the Door, which is called the Multazam, and asks Allah for anything, Allah will surely give it to him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9766
Imam al-Shafi'i (may Allah have mercy on him) said: "I like that when he bids farewell to the House (of Allah), he stands at the Multazam, which is between the Door and the Corner, and says: 'O Allah, the House is Your House, and the servant is Your servant, the son of Your servant and the son of Your maidservant. You carried me upon what You subjected to me of Your creation until You made me travel through Your lands, and You brought me, by Your blessing, until You helped me complete Your rites. So if You are pleased with me, then increase Your pleasure with me; and if not, then (be pleased with me) from now, before my home becomes distant from Your House. Now is the time of my departure, if You permit me, not seeking a substitute for You or for Your House, nor turning away from You or from Your House. O Allah, accompany me with well-being in my body and protection in my religion, make my return good, and grant me obedience to You for as long as You keep me alive.'"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9767