While they were in exile, the land would have its sabbath rests and be able to restore its nutrients. God loved the promised land and would restore it for their return from exile to live again as his holy people with humble hearts.
Verses 36-39 describe how anxious and fragile the people remaining in the land would become. They would totally despair and lose all their spirit and shake at even the slightest blowing of the wind. Without the Lord's blessing, people lose everything even if they remain in the promised land.
Verses 40-46 describe how the Lord would restore them if they repented. He would remember his covenant with the patriarchs of faith Abraham, Isaac and Jacob, and he would bring his people back to the promised land. Even while they were in the land of their enemies, God would not reject them completely because of his faithfulness to his promises to their ancestors.
Faithful God would send his own Son as the promised Messiah who would die as a curse on the cross in our places. Only faith in Jesus can set us free from the curse of sin, not our own obedience.
Application: Father, thank you for your great faithfulness in spite of our rebellion. Thank you for remembering your promises to us when we repent.
One Word: Repent and be restored to the Lord who is faithful to his promises