This corner of the Kaaba is called Rukan Yamani, because it is located on that side of the Kaaba, which faces the land of Yemen. It is located on the wall opposite the wall of Hajar al-Aswad.
Since this corner still stands on the foundation that Ibrahim built (peace be upon him), according to Abdullah ibn Abbas (may Allah be pleased with him) says that the Prophet (saw) made Istilaam out of it.
Istilaam refers to touching the corner, regardless of whether it is done manually or with a kiss. Since the Prophet (saw) touched Rukan Yamaani with his hand, this practice is Sunna. However, there is no harm if a person cannot touch him because of the crowd.
It was the practice of the Prophet (saw), when he passed between Rukan Yamaani and Hajar al-Aswad, he said the following dua: “O Rabbi, grant us (all that is) good in this world, (all that is) good in hereafter (Aakhirah) and save us from punishment by fire (Jahannam). " [Quran 2:201, Surah Bakara, verse 201]
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