On the testing motif, see Brevard S. Childs, The Book of Exodus: A Critical, Theological Commentary, Old Testament Library (Philadelphia: Westminster, 1974), p. 306f. and literature noted by him on p. 305; also see William Henry Propp, Water in the Wilderness: A Biblical Motif and Its Mythological Background, Harvard Semitic Monographs 40 (Atlanta: Scholars Press, 1987), pp. 51–93.