Charles Ellicott Commentary Isaiah 30:18

"And therefore will Jehovah wait, that he may be gracious unto you; and therefore will he be exalted, that he may have mercy upon you: for Jehovah is a God of justice; blessed are all they that wait for him." — Isaiah 30:18 (ASV)

And therefore ... —The words seem to embody the thought that “man’s extremity is God’s opportunity.” Precisely because of this isolated misery Jehovah was “waiting,” i.e., longing, with an eager expectation, to come to the rescue.

And therefore will he be exalted. —A very slight alteration gives a meaning more in harmony with the context, will wait in stillness (Cheyne). If we adhere to the existing text, we must take the meaning will withdraw himself on high, will seem to wait, that He may at last interpose effectually.

A God of judgment. —Better, of righteousness.

All they that wait for him. —This waiting is, as in the first clause, that of wistful longing.