9 We know well, Venerable Brethren, how much store you also set by the Spiritual Exercises; for you gave yourselves to them before you were adorned with the fulness of the Priesthood; and often afterwards, in company with your Priests you have sought them anew in order to refresh your souls with the contemplation of heavenly things. This excellent practice, assuredly, is deserving of our solemn and public commendation. And we commend, likewise, no less warmly those bishops, whether of the Eastern or of the Western Church, who, as we know, have sometimes come together, with their own Patriarch or Metropolitan, to make a pious retreat adapted to their offices and duties. We hope that this luminous example, so far as circumstances allow, may be followed with sedulous emulation. And perchance there would be no great difficulty in this if a retreat of this kind were instituted on the occasion of one of those synods which all the Prelates of an ecclesiastical province celebrate ex officio , whether to provide for the common salvation of souls, or to deliberate on those things which the conditions of the time seem to require. And, indeed We ourselves had determined to do this, with all the Bishops of Lombardy, during the brief space of our rule over the Metropolitan Church of Milan; and, without doubt, we should have accomplished it, in that first year of office, if the inscrutable decrees of Divine Providence had not disposed otherwise of our lowliness. Wherefore, We are well assured that those priests and religious men who, anticipating the law of the Church, in this matter, already frequented the Spiritual Exercises will, hereafter, use this means of acquiring sanctity with yet greater diligence, now that they are more gravely bound to it by the authority of the sacred Canons.
Source: Mens Nostra (Vatican.va)