Isaiah 31:2

Yet he also is wise as well as the shrewd diplomatists who have negotiated this treaty! The words are ironical, yet they have a serious meaning; the prophet, alone in his view of the political situation, reassures himself by thinking of the transcendent wisdom of Jehovah and the fixity of His purpose.

and will bring evil Rather, brings trouble (cf. Amos 3:6) in consequence of His wisdom.

and will not call back(better: and hath not recalled) his words The "words" are such prophecies as Isaiah 28:16 ff., Isaiah 29:14 ff., Isaiah 30:13 f., Isaiah 30:16 ff.

the house of [the] evildoersis Judah (ch. Isaiah 1:4); their help(i.e. "helpers ") is Egypt.