There are several reasons why this is an extraordinary image to use catechetically and why it is so perfectly suited to illustrate Part Three of the Catechism of the Catholic Church.
One reason is that it links those who are going through the RCIA process today to someone who had been through the RCIA in the fourth century! The young man for whom this tomb was made is named Junius Bassus and the inscription across the top of the sarcophagus states clearly that Junius was a ‘neophyte gone to God’, ‘neofitus iit ad deum’.
It may be that he was dying and was baptized on his deathbed; or it may be that he had been a catechumen in the normal way and had been baptized at some point within the previous year. Whatever his particular circumstances, we can see from these earliest times in the Church, that those newly baptised were called those with new (neo) nature (physis), now united with the life of Jesus Christ. ‘New birth, ‘newly planted’ into Christ or ‘newly alive’ are the usual translations for the great event, the great ontological change that takes place at baptism.