Midrasz do Królów II 22:2

R. Samuel b. Nachmeini in the name of R. Jonathan said: "He who says that Joshiyahu sinned, errs; because it is said (II Kings 22, 2) And he did what is right in the eyes of the Lord, and walked in all the ways of his father, David. But how shall we explain the passage (Ib. 23, 25.) And like unto him there was not a King before him, that returned? etc. [which means that he repented after he sinned]. All amounts paid through his kingly judgment from the time he was eight years of age [when he became king], Joshiah refunded to the owners. Will you say that he took from this one [to whom he had previously given] and gave it back to the other [whom he had before unjustly fined]? It therefore says (Ib. ib. ib.) With all his wealth, i.e., he refunded from his private funds [Thus is meant by the Scripture He returned]." And R. Jonathan's opinion differs from Rab, for Rab said: "None is greater among repenters than Joshiyahu in his generation, and only one in our generation. Who is he? Abba, the father of R. Jeremiah b. Abba. And another relation refers this to Acha, the brother of Abba, the father of R. Jeremiah b. Abba, for the master said: 'R. Abba and Acha were brothers.'" R. Joseph said: "There is one more in our generation." Who is he? Ukban b. Nechemia, the Prince of the Exile. And he is the same one called Nathan Tzutzitha. "Once while studying," said R. Joseph, "I dozed off, and saw in my dream an angel stretching out his hands and accepting [Ukban's repentance]."