Manuscripts also differ. Usually the differences are minor—matters of spelling and the like—but occasionally they are significant, as in the case of the Comma Johanneum, a clause in the First Epistle of John that bears explicit witness to the doctrine of the Christian Trinity, but is not found in any manuscript earlier than the 10th century (codex 221), where it is shown as a marginal note.[51] A similar example from the Old Testament is the difference between the Septuagint and Masoretic descriptions of the battle of David and Goliath: the Septuagint version is shorter and avoids the narrative inconsistencies of the familiar Masoretic story, notably the famous incident of Saul asking who David is as though he does not know his own harpist and shield-bearer.