6 Holy Writ declares that between divine charity, which must burn in the souls of Christians, and the Holy Spirit, Who is certainly Love Itself, there exists the closest bond, which clearly shows all of us, venerable brethren, the intimate nature of that worship which must be paid to the Most Sacred Heart of Jesus Christ. If we consider its special nature it is beyond question that this devotion is an act of religion of high order; it demands of us a complete and unreserved determination to devote and consecrate ourselves to the love of the divine Redeemer, Whose wounded Heart is its living token and symbol. It is equally clear, but at a higher level, that this same devotion provides us with a most powerful means of repaying the divine Lord by our own.
Source: Haurietis Aquas (Vatican.va)