Many people are familiar with the picture of Christ standing at a vine-covered building and holding a lantern in his hand as he knocks at the door. He appears to be saying: "Behold, I stand at the door and knock" (Revelation 3:20). This famous painting was done by Holman Hunt. Before it was shown to the public, he asked his fellow artists for their comments. All seemed to agree that it was quite masterful. Then one of them pointed out what he thought was a mistake, saying, "There is no latch on the door." But Hunt replied: "That is no mistake, the door represents the human heart, and the latch is on the inside".
How true that is of our contacts with Christ. All-powerful as he is, he will not force himself upon us.. All he can do is knock at the door of our hearts; we must open the door ourselves. We must open the door because the latch is on the inside. We can treat him as an unwanted stranger and leave him standing outside, or we can welcome him as a friend, opening the door of our hearts willingly.
Ages ago God shared with us in the act of creation. So that his name might never be forgotten, he made a covenant with the Israelites who preserved the worship of the true God through the centuries. God promised to send a Messiah to deliver them. That Messiah came in the person of Jesus Christ. By his suffering and death, and Resurrection he fulfilled the ancient prophecies and proved that he truly was the Son of God. For three long years he taught the apostles, promising that he would send the Holy Spirit to guide and guard them after he went back to the Father. He fulfilled that promise at Pentecost, and the apostles began to spread the Good News of salvation. The life, death, and Resurrection of Jesus became the gist of the apostolic teaching. Those who believed that these events proved he was truly the Messiah were baptized in his name. As followers of Christ they were taught to love God above all and their neighbors as themselves. They used all the means, especially the Eucharistic sacrifice, to increase God's love in their hearts, trusting that one day the promised eternal kingdom would be theirs. It was basically a matter of believing, trusting, and loving. 
But the simplicity of the early Christianity began to vanish after a time. The more the Church grew, the more complex it became. Persecutions, schisms, and reformations (both within and outside the Church) all contributed to its rise and fall. The early Christians certainly viewed Christ as both God and Man. But since they were much closer in time to the human Savior, their religion was very personal. They considered Jesus as a Man who was also God.
Much later, when Christianity became more sophisticated (as the world itself had become), people began to view Jesus more from the angle of a God who became Man. Of course, he has always been both God and Man. But the theologians - those who sought to know more about God - began to discuss, among other things, his divinity, his wisdom, his power, and his glory. This was all well and good; presumably, the more we know about someone, the more we will love that person. But ordinary Christians were not too interested in these wonderful theological findings. They longed for the human Christ. They admired his divine wisdom, but preferred to live by the truth of his words. They were struck by his divine power, but they would rather feel his strength pulsing through their own bodies. They marveled at his divine glory, but they were more eager to receive his grace into their hearts.
Thus the pendulum began to swing back toward a more personal view of Christ. Special devotions like processions in honor of the Eucharistic Christ and Benediction of the Blessed Sacrament arose. Apparitions of our Blessed Mother at Lourdes, Fatima, and Guadalupe came on the scene as an obvious attempt on God's part to bring people closer to Jesus through His Mother. One of the most popular devotions that appeared during those centuries centered on the love which is exemplified in the Sacred Heart of Jesus.