59 On the other hand, love and the human heart do not always go together, since hatred, indifference and selfishness can also reign in our hearts. Yet we cannot attain our fulfilment as human beings unless we open our hearts to others; only through love do we become fully ourselves. The deepest part of us, created for love, will fulfil God’s plan only if we learn to love. And the heart is the symbol of that love.
Source: Dilexit Nos (Vatican.va)