Musnad Ahmad 32:1850

'Abd al-Samad ibn Hassan narrated to us, he said: 'Umarah—meaning Ibn Zadhan—informed us, from Thabit, from Anas, who said: The Angel of Rain asked permission to come to the Prophet, may Allah bless him and grant him peace, and he granted him permission. He said to Umm Salamah: "Guard the door for us; let no one enter." Then Al-Husayn ibn 'Ali came and leaped until he entered. He began climbing onto the Prophet's shoulder, may Allah bless him and grant him peace. The angel said to him: "Do you love him?" The Prophet, may Allah bless him and grant him peace, said: "Yes." The angel said: "Indeed, your nation will kill him, and if you wish, I will show you the place where he will be killed." He said: So he struck with his hand and showed him red soil. Umm Salamah took that soil and tied it in the corner of her garment. He said: "So we used to hear that he would be killed in Karbala."