Richard Hays on interpretation,
That is a way of saying that texts can generate readings that transcend both the conscious intention of the author and all the hermeneutical strictures that we promulgate. Poets and preachers know this secret; biblical critics have sought to suppress it for heuristic purposes. At times, the texts speak through us in ways that could not have been predicted, ways that can be comprehended only by others who hear the voice of the text through us—or, if by ourselves, only retrospectively
To limit our interpretation of Paul’s scriptural echoes to what he intended by them is to impose a severe and arbitrary hermeneutical restriction. In the first place, what he inteded is a matter of historical speculation; in the second place, his intertextual echoes are acts of figuration. Consequently later readers will rightly grasp meanings of the figures that may have been veiled from Paul himself. Scripture generates through Paul new figurations; The Righteousness from Faith finds in Paul a new voice.
Hays, Richard B. Echoes of Scriptture in the Letters of Paul. New Haven: Yale University Press, 1989, p. 33