Bukhari

Narrated Ibn `Abbas: The Prophet once passed by two graves, and those two persons (in the graves) were being tortured. He said, "They are being tortured not for a great thing (to avoid). One of them never saved himself from being soiled with his urine, while the other was going about with calumnies (to make enmity between friends). He then took a green leaf of a date-palm tree split it into two pieces and fixed one on each grave. The people said, "O Allah's Apostle! Why have you done so?" He replied, "I hope that their punishment may be lessened till they (the leaf) become dry."

And Buraidah al-Aslami, the Companion (may Allah be pleased with him), had made a bequest that two branches be placed on his grave. And Abdullah bin Umar (may Allah be pleased with them both) saw a tent pitched over the grave of Abdur Rahman bin Abi Bakr (may Allah be pleased with him), so he said, "O servant! Uproot it, now their deeds will shade them." And Kharijah bin Zaid said, "In the time of Uthman (may Allah be pleased with him), I was a young man and considered the best at jumping, and I would jump over the grave of Uthman bin Maz'un (may Allah be pleased with him) and leap to the other side." And Uthman bin Hakim narrated that Kharijah bin Zaid took his hand and made him sit on a grave, and narrated from his uncle Yazid bin Thabit that sitting on a grave is prohibited for one who sits on it to urinate or defecate. And Nafi' narrated that Abdullah bin Umar (may Allah be pleased with them both) used to sit on graves.

And Buraidah al-Aslami, the Companion (may Allah be pleased with him), had made a bequest that two branches be placed on his grave. And Abdullah bin Umar (may Allah be pleased with them both) saw a tent pitched over the grave of Abdur Rahman bin Abi Bakr (may Allah be pleased with him), so he said, "O servant! Uproot it, now their deeds will shade them." And Kharijah bin Zaid said, "In the time of Uthman (may Allah be pleased with him), I was a young man and considered the best at jumping, and I would jump over the grave of Uthman bin Maz'un (may Allah be pleased with him) and leap to the other side." And Uthman bin Hakim narrated that Kharijah bin Zaid took his hand and made him sit on a grave, and narrated from his uncle Yazid bin Thabit that sitting on a grave is prohibited for one who sits on it to urinate or defecate. And Nafi' narrated that Abdullah bin Umar (may Allah be pleased with them both) used to sit on graves.

Narrated Ibn `Abbas: The Prophet once passed by two graves, and those two persons (in the graves) were being tortured. He said, "They are being tortured not for a great thing (to avoid). One of them never saved himself from being soiled with his urine, while the other was going about with calumnies (to make enmity between friends). He then took a green leaf of a date-palm tree split it into two pieces and fixed one on each grave. The people said, "O Allah's Apostle! Why have you done so?" He replied, "I hope that their punishment may be lessened till they (the leaf) become dry."