Radak #1: Yisrael in Galus ask Hashem to give to us rest.

Radak #2: Return our exile.

Malbim: The author requests a new matter that they did not hope for - to bring the redemption before its time. Coming after the time that the Nevi'im said (70 years) is like reaping a grain field in a good land. He was sure that he will bear sheaves; the Simchah is not so great. For the Ge'ulah to come early is like one who sowed in a dry land.

Rashi: They are like springs of water in a dry land ¹ ; they moisten it. So we will be wet (happy) when You return our exile.

Radak: It is a great Chidush and benefit for springs to go through a dry land. So will be the return of our Galus and salvation of Yisrael. Galus is compared to a dry land, and salvation to springs.