""Greater love than this no man hath, that a man lay down his life for his friends." (John xv. 13.) To show his love for us, what more could the Son of God do than die for us? What more can one man do for another than give his life for him? "Greater love than this no man hath." Tell me, my brother, if one of your servants if the vilest man on this Earth had done for you what Jesus Christ has done in dying through pain on a cross, could you remember his love for you, and not love him?"
Find the full St. Alphonsus Maria de Liguori's sermon: "On the Love of Jesus Christ for Us, and on Our Obligations to Love Him." here: On the Love of Jesus Christ for Us, and on Our Obligations to Love Him - Manna of the Soul