The Glory of the Messianic Age

Optimist or pessimist? Which should the Christian be? Isaiah was both.In this passage, Isaiah uses the term, "In that day." What day is he talking about? When are these things to be fulfilled?
Isaiah is presenting the Messiah as the perfect ruler (verses 1-3) and righteous judge (verses 3-5) who will lift the curse (verses 6-9) on the earth and save humanity (verse 10).