The Solemnity of the Most Sacred Heart of Jesus
is today. There is information on it here.
In 1875, Venerable John Henry Newman, C.O., preached a sermon for this day, of which the following notes survive:

The Sacred Heart

1. INTROD.—Many devotions in Holy Church. This is one which has spread of late years, more, I may say, than any other. Today is the special feast of it; and [this] leads me to explain in what it consists.

2. Our Lord is One. He is the one God. He took on Him a manhood, a body and soul; that body from Mary. Still, He was one, not two—one, as each of us is one.

3. We too, in our way, are each of us one, though we are two—soul and body—and the body has parts; [nevertheless] each of us is one. This is what is meant by speaking of our Lord's [oneness] as we speak of our own.

4. And though each of us is thus composite, we can love each other as one, though of so many parts. And in like manner, though our Lord is God and man, with a soul [and body], we can contemplate Him as one, and worship, love Him as one.

5. Further, if I said I loved the face, or the smile, or liked to take the hand of my father or mother, it would be because I loved them. And so, when I speak of the separate portions of our Lord's human frame, I really am worshipping Him. So in the Blessed Sacrament we do not conceive of His Body and Blood as separate from Him.

6. Devotions at various times [and ages]—the Wounds, the Blood, the Face—and in like manner the Heart. We worship [each] as Him, as that One Person who is God and man; we worship [Him] by the memento, the pledge of His Heart.

7. Why? The Heart a symbol—so the Wounds and the Blood. [In contrast with these] a symbol is sometimes that which [only] expresses and reminds—thus water, oil, wine, bread.

8. What is the Heart the symbol of?—of His love, His affection for us, so that He suffered for us—the agony in the garden.

9. Moreover, of His love in the Holy Eucharist.

10. The Heart was the seat, first, of His love for us; secondly, of His many griefs and sorrows.

{The following were appended, apparently as alternatives:]

7. Of two things especially to remind us now, when the world is so strong—His power and His love. He will overcome by love.

8. The Heart is the emblem of His love—in worshipping It we worship Him.

If it were not a solemnity, today would be the feast of the Martyrs of Uganda.