Isaiah is totally committed to upholding the divine Law in Jerusalem, as was Amos in Bethel and Samaria. As Amos condemned every kind of injustice which he saw in Israel, so Isaiah attacked injustice in Jerusalem. For Isaiah, the way in which justice was administered and the way in which people behaved towards one another was the test of their genuine loyalty to Yahweh. We should note that Isaiah never refers to the events of the Exodus and the Covenant at Sinai explicitly and in this he differs from Amos and particularly Hosea, but the passages of the book which refer to injustice in Judah, particularly chapter 1, assume the Covenant Law as the foundation of life amongst the people of Yahweh.

As Amos condemned empty, insincere worship at Bethel, so Isaiah condemned the sacrifices offered in Jerusalem by disobedient and unjust people who claimed to be worshippers of Yahweh (1: 11-17). As Amos and Hosea had warned the northern people of the coming judgement of Yahweh on their rejection of the covenant faith and Law, so Isaiah warned the people of Jerusalem that Yahweh would not tolerate their injustice, shallow religion and apostasy in the city which claimed to be holy. Yahweh's judgement would fall on the sin of Jerusalem; a faithful remnant would survive the judgement, for God's purposes.