external evidence is lacking, but no less so than in the case of hypothetical Gospel sources (Q; the σημεῖα-source) or earlier traditions (as delineated by form criticism). In fact, the commonly accepted hypothesis that such materials were employed in preaching or catechesis already implies their authoritative character. The leap from such uses in the fifties to the reading of the Gospels in church worship a hundred years later is a reasonable one, even if we cannot document the earlier stages.