The identification of Israel as the vineyard is a surprise. It resolves the riddle of the passage.
Here, a clever play on Hebrew words is used to accuse Israel. The Lord expected justice (Hebrew mishpat) but saw only oppression (mispakh) of the needy. Instead of righteousness (tsedaqah), there were cries of violence (tse‘aqah) against the poor (see Isaiah 1:21–23). These similar-sounding words make the message memorable.