55 The heart, too, has the advantage of being immediately recognizable as the profound unifying centre of the body, an expression of the totality of the person, unlike other individual organs. As a part that stands for the whole, we could easily misinterpret it, were we to contemplate it apart from the Lord himself. The image of the heart should lead us to contemplate Christ in all the beauty and richness of his humanity and divinity.
Source: Dilexit Nos (Vatican.va)