Fear not, O land; be glad and rejoice: for the Lord will do great things. The land had suffered severely from the drought connected with the locusts; but is now summoned to joy and gladness. The prophet assigns for this an appropriate reason: the locusts had done great things in damaging it; Jehovah now does great things in their destruction.
When the earth clothes itself with verdure, and brings forth its fruits and flowers and various products, it is said, by a bold but beautiful personification, to rejoice and even exult. Thus the Latins said in like manner, Rident arva, ridet ager.
Things are now reversed. Instead of mourning, is exultation; instead of mourning and its visible emblem in girding with sadness, there is joy and gladness; instead of the day of the Lord: very great and terrible or fearful, is "Fear not."
Semāchi is fem. imper. Qal in pause for the ordinary simchi.