Romans 15:21

ἀλλὰ καθὼς γέγραπται : Paul's actual procedure corresponded with, and indeed led to the fulfilment of, a famous O.T. prophecy. Isaiah 52:11 exactly as in LXX. It is absurd to argue with Fritzsche that Paul found a prediction of his own personal ministry (and of the principles on which he discharged it), in Isaiah, and equally beside the mark to argue that his use of the passage is “quite in accordance with the spirit of the original”. The LXX is quite different from the Hebrew, and Paul quotes it because he liked to be able to express his own opinion or practice in Scripture language. It seemed to him to get a Divine confirmation in this way; but an examination of various passages shows that he cared very little for the original meaning or application.