After the Babylonian captivity, the people of God find themselves in a general confusion with internal rearrangements and confrontations. In this situation, the main theological question that Trito-Isaiah is called to answer is when will the promised salvation of the people of Israel, as foretold in Deutero-Isaiah, come, which has not yet come. The relevant prophecies of Deutero-Isaiah were not fulfilled. Thus, Trito-Isaiah uses the classic scheme of "sin-repentance-salvation", with the ultimate goal of regulating issues of the post-exilic community in the religious, worship, and social field. The reconstruction of the community is based on social justice, religious and worship revival, which is why the prophet addresses crucial issues such as sin, righteousness, justice, worship, fasting, sacrifice, observance of the Sabbath, Temple and Yahweh, Zion and Yahweh, nations and Yahweh, universality of Yahweh. Zion and Jerusalem play a fundamental theological role in Trito-Isaiah. A new world will arise based on the transformed Zion. The future of the people of Zion, through a new exodus, will be an era of light, peace, and prosperity. The prophet emphasizes that Yahweh is the only God and He regulates creation, history, and events. In this context, the nations that have now known and approached Yahweh will be equal to the Jews and will participate in the terms of the Covenant.