The expression that Jephthah instructs his messengers to begin with, Thus says Jephthah,
is standard ambassadorial language
that heads of state used when addressing each other through their respective messengers (1 Kings 20:2; 2 Kings 9:18–19). It was an expression that was used by imperial powers when they addressed subject states (2 Chronicles 36:23; Ezra 1:2).1
15 and said to him, “Thus says Jephthah: Israel did not take away the land of Moab or the land of the Ammonites,