Sacerdotalis Caelibatus §47

⁴⁷ Our Lord Jesus Christ did not hesitate to confide the formidable task of evangelizing the then-known world to a handful of men to all appearances lacking in number and quality. He bade this little flock not to lose heart, (91) for, thanks to His constant assistance, (92) through Him and with Him, they would overcome the world. (93) Jesus has also taught us that the kingdom of God has an intrinsic and unobservable dynamism which enables it to grow "without [man's] knowing it." (94) The harvest of God's kingdom is great, but the laborers, as in the beginning, are few. Actually, they have never been as numerous as human standards would have judged sufficient. But the heavenly King demands that we pray "the Lord of the harvest to send out laborers into His harvest." (95) The counsels and prudence of man cannot supersede the hidden wisdom of Him who, in the history of salvation, has challenged man's wisdom and power by His own foolishness and weakness. (96)