King of Hearts

The Feast of Christ the King was established by Pope Pius XI in 1925 as an antidote to secularism, a way of life which leaves God out of man's thinking and living and organizes his life as if God did not exist. The feast is intended to proclaim in a striking and effective manner Christ's royalty over individuals, families, society, governments, and nations.

Today's Mass establishes the titles for Christ's royalty over men: 1) Christ is God, the Creator of the universe and hence wields a supreme power over all things; "All things were created by Him"; 2) Christ is our Redeemer, He purchased us by His precious Blood, and made us His property and possession; 3) Christ is Head of the Church, "holding in all things the primacy"; 4) God bestowed upon Christ the nations of the world as His special possession and dominion.

Today's Mass also describes the qualities of Christ's kingdom. This kingdom is: 1) supreme, extending not only to all people but also to their princes and kings; 2) universal, extending to all nations and to all places; 3) eternal, for "The Lord shall sit a King forever"; 4) spiritual, Christ's "kingdom is not of this world".
— Rt. Rev. Msgr. Rudolph G. Gandas, from Catholic Culture

from the Papal decree:

It has long been a common custom to give to Christ the metaphorical title of "King," because of the high degree of perfection whereby he excels all creatures. So he is said to reign "in the hearts of men," both by reason of the keenness of his intellect and the extent of his knowledge, and also because he is very truth, and it is from him that truth must be obediently received by all mankind. He reigns, too, in the wills of men, for in him the human will was perfectly and entirely obedient to the Holy Will of God, and further by his grace and inspiration he so subjects our free-will as to incite us to the most noble endeavors. He is King of hearts, too, by reason of his "charity which exceedeth all knowledge." And his mercy and kindness which draw all men to him, for never has it been known, nor will it ever be, that man be loved so much and so universally as Jesus Christ. But if we ponder this matter more deeply, we cannot but see that the title and the power of King belongs to Christ as man in the strict and proper sense too. For it is only as man that he may be said to have received from the Father "power and glory and a kingdom," since the Word of God, as consubstantial with the Father, has all things in common with him, and therefore has necessarily supreme and absolute dominion over all things created.

FishEaters makes it clear:

God made promises to Father Abraham and King David. These promises are revealed in Genesis 22:16-18 and II Kings 7:10-19 respectively:

Genesis 22:16-18
By my own self have I sworn, saith the Lord: because thou hast done this thing, and hast not spared thy only begotten son for my sake: I will bless thee, and I will multiply thy seed as the stars of heaven, and as the sand that is by the sea shore: thy seed shall possess the gates of their enemies. And in thy seed shall all the nations of the earth be blessed, because thou hast obeyed my voice.

II Kings 7:10-19
And I will appoint a place for my people Israel, and I will plant them, and they shall dwell therein, and shall be disturbed no more: neither shall the children of iniquity afflict them any more as they did before, from the day that I appointed judges over my people Israel: and I will give thee rest from all thy enemies. And the Lord foretelleth to thee, that the Lord will make thee a house. And when thy days shall be fulfilled, and thou shalt sleep with thy fathers, I will raise up thy seed after thee, which shall proceed out of thy bowels, and I will establish his kingdom. He shall build a house to my name, and I will establish the throne of his kingdom for ever. I will be to him a father, and he shall be to me a son: and if he commit any iniquity, I will correct him with the rod of men, and with the stripes of the children of men. But my mercy I will not take away from him, as I took it from Saul, whom I removed from before my face. And thy house shall be faithful, and thy kingdom for ever before thy face, and thy throne shall be firm for ever. According to all these words and according to all this vision, so did Nathan speak to David.

And David went in, and sat before the Lord, and said: Who am I, O Lord God, and what is my house, that thou hast brought me thus far? But yet this hath seemed little in thy sight, O Lord God, unless thou didst also speak of the house of thy servant for a long time to come: for this is the law of Adam, O Lord God.
These prophecies are fulfilled in Christ, Who is King of Israel ("Christ" means "Anointed One," and the anointing referred to is the anointing King David received). Our Lord, though, is not only the ruler of the restored Davidic Kingdom (the Church), but is the King of Kings -- the King of All. The only way for peace to have a chance in this world is for all to see Him for Who He is: the King before Whom we must bow and Whom we must obey.

Though this Feast is a new one, promulgated by Pope Pius XI in 1925 in his Encyclical Quas Primas, it is a most awesome and important one! Vive Christus Rex!

On this day, we pray for the conversion of all to Christ, and for all governments to recognize Him as King and conform their laws to His teachings. This is the only way to peace!

Apocalypse 19:15-16:
And out of his mouth proceedeth a sharp two-edged sword, that with it he may strike the nations. And he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness of the wrath of God the Almighty. And he hath on his garment and on his thigh written: KING OF KINGS AND LORD OF LORDS.