Ibn ‘Umar said that he heard God's messenger say, “The Corner and the Station are two of the sapphires of paradise whose light God has obliterated. If He had not done so, they would have illuminated everything between the East and West."
He reported God’s messenger as saying concerning the stone, “I swear by God that God will certainly raise it up on the day of resurrection with eyes with which it will see and a tongue with which it will speak, and it will give testimony about those who touched it in a proper manner."
Ibn ‘Umar used to press towards the two corners in a manner I have not seen any of the companions of God’s messenger press. He said, “If I do so, it is because I heard God’s messenger say that stroking them is an atonement for sins; and I heard him say that if anyone goes round this House for a week and counts his circuits, it will be like setting free a slave; I heard him say that no one will place one foot on the ground and raise the other without God removing a sin from him on account of it and recording a blessing for him on account of it.”
He reported God's messenger as saying, “The black stone descended from paradise whiter than milk, but the sins of the descendants of Adam made it black."
Ahmad and Tirmidhi transmitted it, the latter saying that this is a hasan sahih tradition.