Jeremiah 7:1-8:3 is a prose section sometimes called the "Temple Sermon." Jeremiah apparently harangued people with this message at the doors of the temple. Their trust that the very existence of the temple would keep them safe and Jersualem inviolable was ill-founded:
Do not trust in deceptive words and say, “This is the temple of the Lord, the temple of the Lord, the temple of the Lord!”
The Judahites have failed to do justice. Verses 5-7 hark back to Deuteronomy 28-30. The temple has become a "den of robbers" (v. 11). Jesus will cite this verse when he upsets the temple in his own day (Mark 11:17 and parallels).
The old temple at Shiloh was destroyed (vv. 12-15). Its existence didn't spare the Israelites from being conquered (v. 15). Neither will the Jerusalem temple save the Judahites.
In verses 16 ff. YHWH once again expresses his anger about Judah's idolatries. In verses 25-26, the prophet cites the exodus from Egypt, this time taking a less romantic view than in chapter 2:
From the time your ancestors left Egypt until now, day after day, again and again I sent you my servants the prophets. But they did not listen to me or pay attention. They were stiff-necked and did more evil than their ancestors.
Verse 31 brings the most scandalous accusation against Judah. The people have practiced child sacrifice in the valley of Ben-Hinnom (which gives its name to Gehenna, hell).
As a result of all this, Judah and Jerusalem will become a wasteland of open graves and rotting corpses (7:32-8:3).
Jeremiah 8:4-17 is a poetic passage detailing again the sins of Judah's people, priests, and prophets. Their repentance comes too late to prevent disaster.
Jeremiah 8:18-9:26 is a collection of poems which the New Interpreters Study Bible interprets as a conversation among several voices including YHWH, Jeremiah, and Judah. Mostly they lament the devastation of Jerusalem. 8:22 asks the question "Is there no balm in Gilead?" which is the source of a well-known spiritual song and which is quoted in Poe's famous poem The Raven.
The Apostle Paul quotes Jeremiah 9:24 in his first letter to the Corinthians though, as usual, he shows no concern for the original context of the quote.
This is what the Lord says:
“Let not the wise boast of their wisdom
or the strong boast of their strength
or the rich boast of their riches
but let the one who boasts boast about this:
that they have the understanding to know me,
that I am the Lord, who exercises kindness,
justice and righteousness on earth,
for in these I delight,”
declares the Lord.
In 9:25-26 YHWH announces that he will deal with those who are uncircumcised. the Gentiles whose foreskins are not circumcised and the Judahites whose hearts are uncircumcised.
Biblical quotations are from the New International Version. Next: Jeremiah 10-13