The second edition of this companion to the Greek New Testament discusses textual variations based on the critical apparatus. It contains a thorough explanation of each textual decision that appears in UBS4. "Most commentaries on the Bible seek to explain the meaning of words, phrases, and ideas of the scriptural text in their nearer and wider context; a textual commentary, however, is concerned with the prior question, What is the original text of the passage? That such a question must be asked – and answered! – before one explains the meaning of the text arises from two circumstances: (a) none of the original documents of the Bible is extant today, and (b) the existing copies differ from one another."