ירמיהו ג:ז פירוש: רש״י

And I said through My prophets, Amos and Hosea son of Beeri and the other prophets, “You shall return to Me.”

And her treacherous sister Judah saw it i.e., saw all this. The appellation “treacherous” is harsher than “backsliding.” Israel, since they were the first to sin, and they did not see any retribution from which to learn and to repent, are called “backsliding.” Judah, who saw that these went in exile and did not receive correction, are called “treacherous.”