Before she discovered Christian Science and began to teach this subject, Mary Baker Eddy had experience as a teacher of other subjects. Besides conducting an infants' school for a short time, she had taught frequently or regularly in a Congregational Sunday School, and she had taught occasionally in the place of absent teachers in an academy, the New Hampshire Conference Seminary. She had also spoken and written on topics of public interest during the years preceding her discovery of this Science. These activities furnished a certain amount of preparation for teaching Christian Science. She depended directly, however, upon divine Mind, not only for her comprehension of this subject, but also for her ability to communicate it effectively. A member of her first class in Christian Science (Samuel Putnam Bancroft, 1870) has said, "At all times she seemed conscious of a wisdom beyond her own."
One of the first problems of the first teacher of Christian Science was to choose the best methods for teaching this subject. During 1867-69, when not otherwise occupied, Mrs. Eddy taught pupils one by one and for indefinite times. In 1870, she began to hold classes and give them a course of twelve lessons. From the first, she based her teaching of pupils on the Bible and on written texts which she supplied. Thus, from experience and divine guidance she adopted "class instruction" (personal instruction to classes varying in size, based upon the two textbooks of Christian Science — the Bible and "Science and Health with Key to the Scriptures") as a permanent part of Christian Science methods. This adoption is now witnessed by Articles XXVI-XXX of her Church Manual, including the following part of Article XXVII, Section 5: "No member of this Church shall advise against class instruction."
The greatest of all teachers could say, "The word which ye hear is not mine, but the Father's which sent me"(John 14:24). Mrs. Eddy could say this, too. Jesus also said, "Take heed therefore how ye hear" (Luke 8:18). Mrs. Eddy likewise sought to make sure that "however little be taught or learned, that little shall be right" (Retrospection and Introspection 61:28). Thus, she commended "the simple sense one gains of this Science through careful, unbiased, contemplative reading of my books" (Miscellaneous Writings 43: 12), and she made provisions in her Church Manual to the effect that the Bible and her writings shall be the criterion for teaching and learning Christian Science (Article IV, Section 1; Article XII, Section 2; Article XXVI, Section 6).