Jeremiah 47:1 - Dummelow's Commentary on the Bible

Before that Pharaoh smote Gaza] The main views as to the date of this prophecy are (a) that the 'Pharaoh 'is Necho, and that he captured Gaza about the time of his defeat of Josiah's army at Megiddo (608 b.c.); (b) that the reference is to the same king, as having taken Gaza on his way back from his defeat at Carchemish (605 b.c.); (c) that the 'Pharaoh' is Hophra (588-570 b.c.), and that he captured Gaza in the course of an expedition against Tyre and Sidon.