3 And rightly indeed is that said, Venerable Brethren. For is not the sum of all religion and therefore the pattern of more perfect life, contained in that most auspicious sign and in the form of piety that follows from it inasmuch as it more readily leads the minds of men to an intimate knowledge of Christ Our Lord, and more efficaciously moves their hearts to love Him more vehemently and to imitate Him more closely? It is no wonder, therefore, that Our Predecessors have constantly defended this most approved form of devotion from the censures of calumniators, and have extolled it with high praise and promoted it very zealously, as the needs of time and circumstance demanded. Moreover, by the inspiration of God's grace, it has come to pass that the pious devotion of the faithful towards the Most Sacred Heart of Jesus has made great increase in the course of time; hence pious confraternities to promote the worship of the Divine Heart are everywhere erected, hence too the custom of receiving Holy Communion on the first Friday of every month at the desire of Christ Jesus, a custom which now prevails everywhere.
Source: Miserentissimus Redemptor (Vatican.va)