The Bible states that, “nothing impure can enter Heaven” (Rev. 21:27). Because of our sinful nature, purification must take place at some point before we can enter Heaven. The Church teaches us that this purification happens either on Earth or in Purgatory. The practice of praying for the dead as they go through this time of purification is a practice that goes back centuries. There is an example of it in 2 Maccabees: “Thus he made atonement for the dead that they might be absolved from their sin” (2 Macc. 12:46).