10 For even though the devotion to the Sacred Heart of Jesus has triumphed so to speak, over the errors and the neglect of men, and has penetrated entirely His Mystical Body; still there are some of Our children who, led astray by prejudices, sometimes go so far as to consider this devotion ill-adapted, not to say detrimental, to the more pressing spiritual needs of the Church and humanity in this present age. There are some who, confusing and confounding the primary nature of this devotion with various individual forms of piety which the Church approves and encourages but does not command, regard this as a kind of additional practice which each one may take up or not according to his own inclination.
Source: Haurietis Aquas (Vatican.va)