One of the famous religious paintings is by William Holman Hunt. It is called the "The Light of the World".
It was an allegorical painting that represented Jesus carrying a lantern and knocking on a long unopened door that had overgrown weeds.
It represented what the Lord was saying in the 1st reading: Look, I am standing at the door and knocking; if one of you hears me calling, and opens the door, I will come in to share his meal, side by side with him.
The door in the painting has no handle, and can therefore be opened only from the inside, and the night scene represented the need for light.
Yet Jesus is carrying the lantern and persists in knocking on the door.
He knows that the door of the human heart will eventually open to him.
The tax-collector Zacchaeus in the gospel was one example of the door of the heart opening to the light of Christ.
Let us also persist in praying for ourselves and for those in need of conversion and salvation.
The persistent knocking of Jesus and the light of His love, coupled with our fervent prayers will open the hardest of hearts.
The reason why Jesus came is to knock on our hearts and to seek out and save what was lost.