9 In favour of those who shall do as We have above laid down, We are pleased to open the heavenly treasure-house of the Church that they may find therein at once encouragements and rewards for their piety. We therefore grant to all those who, in the prescribed space of time, shall have taken part in the public recital of the Rosary and the Litanies, and shall have prayed for Our intention, seven years and seven times forty days of indulgence, obtainable each time. We will that those also shall share in these favours who are hindered by a lawful cause from joining in these public prayers of which We have spoken, provided that they shall have practiced those devotions in private and shall have prayed to God for Our intention. We remit all punishment and penalties for sins committed, in the form of a Pontifical indulgence, to all who, in the prescribed time, either publicly in the churches or privately at home (when hindered from the former by lawful cause) shall have at least twice practiced these pious exercises; and who shall have, after due confession, approached the holy table. We further grant a plenary indulgence to those who, either on the feast of the Blessed Virgin of the Rosary or within its octave, after having similarly purified their souls by a salutary confession, shall have approached the table of Christ and prayed in some church according to Our intention to God and the Blessed Virgin for the necessities of the Church.
Source: Supremi Apostolatus Officio (Vatican.va)