The Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, said: “Once the placement of the bricks (Laban) over the deceased is completed, soil should be poured over the bricks. Those who followed the funeral procession should pour the soil using the back of their hands while saying: "Indeed, we belong to Allah سبحانه وتعالى, and indeed, to Him we shall return." It is disliked for a person to pour soil over the grave of his son, and likewise, it is disliked for a son to pour soil over the grave of his father, as it may harden the heart towards close relatives (Dhu al-Arham).”
Commentary #24