In Matthew 9:35ff., Jesus sees Israel battered and cast down, like sheep without a shepherd. Then he says to his disciples, “The harvest is plentiful; the workers are few.”
Why does the imagery change from animals to plants, from sheep/shepherd to harvest/workers? It would make sense for Jesus, seeing the crowds like sheep without a shepherd, to tell his disciples to pray for workers to gather in the flock.
Jakob van Bruggen (Matteüs) proposes that Jesus is speaking, not of workers needed for gathering in the harvest but of workers needed for distributing the plentiful harvest to care for the flock.
I’m not persuaded that explanation really works. After all, “Send out workers into his harvest” is not the clearest way to say “Send workers out to Israel with the food that has been harvested”!
On the other hand, when Jesus does send out his disciples, he returns to the imagery of sheep/shepherd (10:6: “Go to the lost sheep of the house of Israel”) and he speaks, not of gathering, let alone of gathering in a harvest, but rather of giving (10:8: “Freely you have received; freely give”).