Mother Teresa had this well known poem hung to inspire service to others. 
You can never lose love! All the love you give to the world has its source in God. When love is given away by us to others, its scent is left living sweetly in our own souls. Human persons are made in the image of God (Genesis 1:27). This image includes intellectual gifts such as the ability to seek the truth and gain knowledge. This image also includes the capacity to love which expresses itself in using one’s will to bring about what is good. In order to know what is good, one needs to know the truth. Therefore, the possession of truth is the foundation to being free to love. Love without knowledge of the truth does not know what is good. Likewise, knowledge without love cannot act.
God is all good. God is filled with all truth and knowledge. To love God is to love what is good. The fruit of loving God is the pursuit of reflecting God’s goodness and truth in our own lives. St. Augustine writes, “But it is by love that we must stand firm to this and cleave to this, in order that we may enjoy the presence of that by which we are, and in the absence of which we could not be at all” (de Trinitate VIII, iv). It is the tiniest seed of love planted within our own hearts that is continuously fueled by the grace of God to burn brighter and love fuller. Without this grace from God we could not love at all. Love binds the will to act in the ways of truth and righteousness.
To love what is good is to love what God loves. St. Augustine writes, “But this is true love, that cleaving to the truth we may live righteously, and so may despise all mortal things in comparison with the love of men, whereby we wish them to live righteously. For so we should be prepared also to die profitably for our brethren, as our Lord Jesus Christ taught us by His example” (de Trinitate VIII, vii). If one is prepared to die for others in imitation of Jesus Christ, it is essential to know the truth. Without the truth one could die for a lie and there is no good in dying for lies.
Love and knowledge work together to direct our hearts and actions to do what is good, right, and true. Love of the good draws us into union with God who is all good. Possession of the truth tells us who we are called to die for.
Let no one say, I do not know what I love. Let him love his brother, and he will love the same love. For he knows the love with which he loves, more than the brother whom he loves. So now he can know God more than he knows his brother: clearly known more, because more present; known more, because more within him; known more, because more certain. Embrace the love of God, and by love embrace God. (de Trinitate VIII, viii)
This love for what is good is expressed through our love for other people; however, it is not really about them. As St. Augustine writes, “For he knows the love which he loves, more than the brother whom he loves.” The love that we express to others never leaves us. As beloved “adopted” children of God the Father, we are in the Father and the Father lives in us.
Joyful Living 