Joel 2:21

O land more exactly, O ground; i.e. the soil which until now has been "mourning" (Joel 1:10) under the sore visitation.

for Jehovah hath done great things exactly the same phrase as in Joel 2:20, the past tense, however, being here the "prophetic past" (comp. on Amos 5:2), and describing in reality what Jehovah will do. For the application of the phrase to Jehovah, see Psalms 126:2-3.