The Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, said: “It is recommended to write on his shirt, his outer shroud (Hibarah), or the cloth that serves its place, or on the two palm branches, using one’s finger: 'So-and-so bears witness that there is no god but Allah سبحانه وتعالى.' If this is written with the soil from the grave of Husayn ibn ‘Ali عليه السلام, it carries great merit. However, it should not be written with ink or any dyes.”
Commentary #17