For the returned exiles, farming was a painful pursuit since the ground had become hard and wild, because no one had cultivated it. However, the farmer who worked hard could expect a rich harvest in the future. Future joy would replace present weeping. Undoubtedly the psalmist used this terminology to represent the restoration of the nation as well as its crops. This seems clear from the preceding verses. His point was that even though the Jews who had returned had a hard time reestablishing the life and institutions of Judaism, they could anticipate that God would reward their labor. It was as certain as reaping follows sowing (cf. Galatians 6:7). [source][source][source]
The initial flush of enthusiasm and success that those who seek to honor God experience, must continue, even if the work is slow, hard, and discouraging. God"s people can look forward with hope to a rewarding harvest in the future if they faithfully persevere in carrying out the work He has ordained (cf. Matthew 13:1-8; Matthew 13:18-23; Galatians 6:9). [source][source][source]