When going to the COnvitto Ecclesiastico to study or to write, he handwritten sheets of Historia Sacra to the porter and read; on his return, he would ask whether he had understood what it is about. If not, Don Bosco would rewrite those pages to make them even simpler and easier to understand.
This work, some 200 pages, published by Speirani and Ferrero, presented the most important events of the Bible in correct, simple, clear language which made it easy for youngsters to grasp its meaning and remember they had read.
The book of Don Bosco can be summarized into three points:
1. The Messiah had certainly come, because all the prophecies were fulfilled in Jesus Christ.
2. The Messiah had founded a Church, the sole hope of all salvation for all men, infallible in its teachings and in its interpretation of the Bible, indefectible to the end of time because of the unfailing assistance of its founder.
3. This Church is the Roman Catholic Church, which alone through the centuries has preserved the truth taught and confirmed by Jesus Christ.
Its objectives included the following:
- Refute the allegation of Protestants without the publicity and controversy.
- Protect the boys from dangerous errors.