The Massorah (Appendix 30), that is to say, the small writing in the margins of the standard Hebrew codices, as shown in the plate at the bottom of Appendix 30, consists of a concordance of words and phrases, etc., safeguarding the Sacred Text.
  A note in the Massorah against several passages in the manuscripts of the Hebrew Bible states: "This is one of the Eighteen Emendations of the Sopherim," or words to that effect.
  Complete lists of these emendations are found in the Massorah of most of the model or standard codices of the Hebrew Bible, and these are not always identical; so that the total number exceeds eighteen: from which it would appear that these examples are simply typical.
  The Siphri ¹ adduces seven passages; the Yalkut,² ten; the Mechiltha,³ eleven; the Tanchuma,⁴ seventeen;
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   ¹ An ancient commentary on Leviticus (circa A.D. 219-47).
  ² A catena of the whole Hebrew Scriptures, composed in the eleventh century, from ancient sources by Rabbi Simeon.
  ³ An ancient commentary on Exodus, compiled about A.D. 90 by Rabbi Ishmael ben Elisa.
  ⁴ A commentary on the Pentateuch, compiled from ancient sources by Rabbi Tanchuma ben Abba, about A.D. 380.

while the St. Petersburg Codex gives two passages not included in any other list (Malachi 1:12; 3:9; see below).

  These emendations were made at a period long before Christ, before the Hebrew text had obtained its present settled form, and these emendations affect the Figure of Speech called Anthropopatheia. See Appendix 6.

  The following is a list of the eighteen "Emendations," together with eight others not included in the official lists. Particulars will be found on consulting the notes on the respective passages.