Deuteronomy 14:1
New International Version
14 You are the children of the Lord your God. Do not cut yourselves or shave the front of your heads for the dead,
The actions here refer to a cult of the dead. Many other religions today have some kind of worship of or service to the dead. Christianity and Judaism are very different from other religions because they focus on serving God in this life. Do not let concern or worry over the dead distract you from the tasks that God has for you while you are still alive.
Spirit and Truth