Behold. Figure of speech Asterismos.
hand. Figure of speech Anthropopatheia.
not shortened. Reference to Pentateuch (Numbers 11:23). Compare Isaiah 50:2. The phrase occurs nowhere else in the O.T.
Related Commentaries of Isaiah 59:1
Isaiah 59:1
1 Behold, the LORD'S hand is not shortened, that it cannot save; neither his ear heavy, that it cannot hear: