Both the ministry of God’s servants in the Old Testament and New Testament have certain qualities represented in these stones. Jackson keenly explains these passages to demonstrate that ministers labor after the rich endowments and virtuous habits of grace, which they receive by co-working with God, and they do this by frequent repeated acts of prayer and preaching, to introduce such grace into their own soul and the souls of others by the power of God.
The stones (sardius, topaz, emerald, carbuncle, sapphire, diamond, ligure, achate, amethyst, beryll, onyx, and jasper) show in each of their distinct respects, how a minister is to be worthy of the office of a servant, a comfort to the people, a light or fire in preaching the word, a chaste and holy man, one with a mind set on heaven, and the ability to bring the people "up to God" in preaching and prayer, and much more. In Jackson's explanation of each stone, he demonstrates the office and disposition of every true minister of the Gospel, as well as the description of their work, in "the virtue" of the stones and the meaning behind "the color" of each stone.
This work is not a scan or facsimile, has been carefully transcribed by hand being made easy to read in modern English, and has an active table of contents for electronic versions.
John Jackson (1600-1648) was a Westminster Puritan divine with a hearty theological intellect, and tender pastoral understanding.