39 May this, Our letter, be a pledge of spiritual resurrection for your country, as We have wished to date it on the Feast of the Resurrection as a paternal auspice that, since you have been so vividly participating in the sufferings of Christ, so you may likewise be participants in His resurrection. Given at St. Peter's in Rome on the Feast of the Resurrection, March 28, 1937, the fifteenth year of Our Pontificate.
Source: Firmissimam Constantiam (Vatican.va)