Jeremiah 26:6

Then will I make this house like Shiloh, and will make this city a curse to all the nations of the earth.

The warning is conditional: if Judah refuses to obey God's law and listen to His prophets and persists in its evil course, He will make the temple like Shiloh and make Jerusalem a curse among the nations. To be made like Shiloh recalled Israel's defeat by the Philistines and the capture of the ark in a calamity that came because sin was treated lightly and left unchecked and uncorrected. That calamity included the death of many Israelites. It included also the deaths of Eli and his sons.

Temple services and respect for God's commandments cannot protect people from judgment while they continue in wickedness and refuse repentance and obedience. For just as the ark did not guarantee Israel victory over the Philistines without repentance, observance of temple services could not shield the Jews from punishment. Yet the warning itself gave the people an opportunity to repent and avert the threatened judgment. The priests and people heard it as a prophecy that the temple would become like Shiloh and Jerusalem would be left desolate, and they grew angry and threatened Jeremiah with death for declaring it.

The verse warns those responsible for the church to remove wrongdoing that dishonors God's cause. The threatened desolation of Jerusalem warns those who profess to keep God's law, including modern Israel, that refusing to repent, obey God's word, and accept correction brings serious consequences.