Fausset's Bible Dictionary
("a stone".) A fortress conquered by Sennacherib (2 Kings 19:12), probably on the western side of Euphrates; joined with Haran. Ptolemy (2 Kings 5:15) mentions a Resapha in the Palmyrene district.
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Fausset, Andrew R. Entry for 'Rezeph'. Fausset's Bible Dictionary. https://www.studylight.org/dictionaries/eng/fbd/r/rezeph.html. 1949.