The LDS Church believes that this is a reference to vicarious work for the dead which was practiced by the ancient Christian Church and considered orthodox in Early Christianity, including by the Apostle Paul, hence his use of it as an example of the correct doctrine of the resurrection. This is the origin of the LDS practice of baptism for the dead. As such, a great deal of LDS doctrine and practice is tied to the idea of the continued existence and activity of the human spirit after death and before judgment.