Praying is Commitment to Action
Jesus taught that praying is committing to act; he expects us to commit to what we pray for. The disciples whom Jesus asked to pray for laborers are the first batch of laborers that he had in mind. They may pray for more laborers like them, but they cannot shun their personal responsibility to be harvesters that they prayed for. Praying for a cause is committing to that cause. Without that commitment prayer turns useless.