Jesus" figure of speech in addressing His disciples, however, was an agricultural one. He wanted to infuse His compassion for the multitudes into them. Jesus viewed Israel as a field composed of many stalks of grain. They needed gathering for placement in the barns of the kingdom. They would die where they were and the nation would suffer ruin if workers did not bring them in soon. Unfortunately there were not enough workers to do this massive task. Consequently Jesus commanded His disciples to beseech God, the lord of the harvest, to provide additional laborers for His harvest. [source][source][source]
The picture is of imminent change. A change was coming whether or not the Israelites accepted their Messiah. It would either be beneficial or detrimental to the nation. An adequate number of workers was one factor that would determine the way the change would go. Evidently Matthew expected his readers to understand "disciples" as all who were in a learning relationship to Jesus then rather than just the Twelve. That is the way he used the term so far in this Gospel (cf. Matthew 10:1). [source][source][source]