23 Venerable Brethren, do all you can and spare no effort to see to it that the clergy entrusted to your care may enjoy living and working conditions that will best foster and be of service to their ardent zeal. This means that every effort should be exerted to eliminate the dangers that arise from too great an isolation, to issue timely warnings against unwise or imprudent actions, and last of all to check the dangers of idleness or of too much external activity. In this regard, you should recall the wise directives issued by Our immediate Predecessor in the Encyclical Sacra Virginitas . (34)
Source: Sacerdotii Nostri Primordia (Vatican.va)