Tosefta על ירמיהו 3:14

And everyone who [attempts to] return among these, we don't ever accept them back, the words of Rabbi Meir. Rabbi Yehudah says, [if] they returned publicly, we accept them back, [but] if privately, we don't accept them back. Rabbi Shimon and Rabbi Joshua son of Karcha say, we accept them back either way, as it is said (Jer. 3:14), "Turn back, rebellious children [declares the LORD, etc.]."