204 Never be discouraged by the difficulties that arise, and never let your pastoral zeal grow cold. "Blow the trumpet in Sion . . . call an assembly, gather together the people, sanctify the Church, assemble the ancients, gather together the little ones, and them that suck at the breasts," and use every help to get the faithful everywhere to fill the churches and crowd around the altars so that they may be restored by the graces of the sacraments and joined as living members to their divine Head, and with Him and through Him celebrate together the august sacrifice that gives due tribute of praise to the Eternal Father.
Source: Mediator Dei (Vatican.va)