A.T. Robertson Commentary Luke 10:2

"And he said unto them, The harvest indeed is plenteous, but the laborers are few: pray ye therefore the Lord of the harvest, that he send forth laborers into his harvest." — Luke 10:2 (ASV)

Harvest (θερισμος). Late word for the older θερος, summer, harvest. The language in this verse is verbatim what we have in Mt 9:37,38 to the Twelve. Why not? The need is the same and prayer is the answer in each case. Prayer for preachers is Christ's method for increasing the supply.