John Chrysostom
But how does He give the name of harvest to a work only just now at its beginning? the plough not yet put down, nor the furrows turned, He yet speaks of harvests, for His disciples might waver and say, How can we so small a number convert the whole world, how can foolish men reform the wise, naked men those that are armed, subjects their rulers? Lest they should be disturbed then by such thoughts, He calls the Gospel a harvest; as if He says, All things are ready, I send you to a gathering of fruits already prepared. Ye can sow and reap the same day. As then the husbandman goes out to harvest rejoicing, much more also and with greater cheerfulness must you go out into the world. For this is the true harvest, which shews the fields all prepared for you.
But he afterwards increased them greatly, not by adding to their number, but awarding to them power. He implies that it is a great gift to send labourers into the divine harvest, by His saying that the Lord of the harvest must be prayed to upon this account.