Midrasch zu Hoschea 2:28

In the future exiles will not be redeemed except as a reward for faithfulness, as it is said: Come with me from Lebanon, my bride, with me from Lebanon; look from the top of Amana (Song 4:8). It says likewise: And I will betroth thee unto Me in faithfulness (Hos. 2:28). Thus you learn that faith is powerful, for in reward for faith, the Shekhinah hovered over them and they sang the song, as it is said: And they believed in the Lord … and Moses sang (Exod. 14:31–15:1), and it says also: Then believed they his words; they sang his praise (Ps. 106:12).