Ch. 26 is a biographical account of Jeremiah. Most scholars think that 26:2-6 is a summary of Jeremiah's temple sermon (see ch. 7), which serves as an introduction to the narrative that follows (vv. 7-24). Others regard 26:2-6 as the original sermon. Consult other commentaries for a discussion of Jeremiah's temple sermon.
Jeremiah's sermon (26:1-6) stresses the need to preach relentlessly to those who practice religion without acknowledging that they must repent of their evil. Yahweh is always hopeful that his word might bring about the repentance of sinners. He desires to cancel his judgment against them. It is this wish that compels him to send his messengers again and again with urgency to proclaim his law to his people. The house of God, which does not respond to the display of Yahweh's grace, is on the path to destruction.
Jeremiah encountered opposition because of his faithful preaching and his boldness to attack a shallow theology promoted by the popular leaders (26:7-11). Jeremiah's strong conviction that he was Yahweh's spokesman (“The Lord sent me to prophesy”) enabled him to face his judges without fear (vv. 12-15). Though he was at the mercy and goodwill of these men, his goal was to lead them to conviction and conversion (reform your ways).
Boldness was a characteristic of Israel's prophets (26:16-19). The prophetic tradition, though it was strongly influenced by the Zion theology, refused to accept a blind belief in the inviolability of the temple and the city. The emphasis here is also on the conditional character of Yahweh's threat of punishment; he is not a static and capricious deity but a gracious God who extends mercy to sinners who fear the Lord and seek his favor (v. 19). The parenthetical story of Uriah shows that the threat against Jeremiah's life was real and that his escape was providential (vv. 20-24).