Psalms of Solomon, and portions of the Sibylline Oracles.1 Parallels to other works should be held as tentative until further evidence is forthcoming. When listing allusions to the Old Testament in Revelation we are obviously, then, dealing in probabilities. In many cases neither the external nor the internal evidence is strong enough to be certain that a particular expression is derived from a specific literary source.2 In such cases there is a necessary element of subjectivity in the evaluation