A.T. Robertson Commentary John 5:47

"But if ye believe not his writings, how shall ye believe my words?" — John 5:47 (ASV)

His writings (τοις εκεινου γραμμασιν). Dative case with πιστυετε. See Lu 16:31 for a like argument. The authority of Moses was the greatest of all for Jews. There is a contrast also between

writings (γραμμασιν, from γραφω, to write) and

words (ρημασιν, from ειπον). Γραμμα may mean the mere letter as opposed to spirit (2 Corinthians 3:6; Romans 2:27,29; 2 Corinthians 7:6), a debtor's bond (Luke 16:6f.), letters or learning (John 7:15; Acts 26:24) like αγραμματο for unlearned (Acts 4:13), merely written characters (Luke 23:38; 2 Corinthians 3:7; Galatians 6:11), official communications (Acts 28:21), once ιερα γραμματα for the sacred writings (2 Timothy 3:15) instead of the more usual α αγια γραφα. Γραφη is used also for a single passage , but βιβλιον for a book or roll (Luke 4:17) or βιβλος (Luke 20:42). Jesus clearly states the fact that Moses wrote portions of the Old Testament, what portions he does not say. See also Lu 24:27,44 for the same idea. There was no answer from the rabbis to this conclusion of Christ. The scribes (ο γραμματεις) made copies according to the letter (κατα το γραμμα).