Evangelists often use the picture by Holman Hunt of Jesus knocking at a door. There is no handle on the outside. The person needs to open the door from the inside, and let Him in. This is based on the text : "I am standing at the door knocking; if you hear my voice and open the door, I will come in to you and eat with you, and you with me" (Revelation 3:20).
These words are actually addressed to the Church of Laodicea, which is "neither hot nor cold". The text seems to refer to the Son of God being invited in to that Church's communion service. But the image of being invited in, rather than excluded, is also important for individuals.
Many parents find that in his teens their son closes them out. He still eats with them, does things with the family, and expects his pocket money and the use of the car. But he will not let his mother (and/or father) into how he lives his life, his heart feelings and longings.
Yesterday a woman told me with great joy that their daughter had suddenly "let her in." What she meant was that for several years there had been no heart to heart communication. As a mother she had been excluded. Now one might say that the daughter had been born again into a loving relationship with her parents.
Being born again is not a question of going forward and praying the
right prayer at a Billy Graham meeting, though that may be very helpful.
What counts is that right now you have let Jesus in. And the evidence is
not that you took some step of faith some time in the past, but that right
now day by day you share your deepest feelings, hurts, doubts, failures,
fears, and problems with Him. In other words you have let Him in, as opposed
to excluding Him. After a bit you will find that you are in turn let in
to God's concerns for you, your family, and others in the world.