It is a gift, nothing that you have ever done can earn you closeness to God. Jesus Christ died on the cross to take away our sins or we could never come close to God. Salvation is like going through a door. Shepherds in those days when they wanted to bed their sheep down for the night would herd their sheep into an enclosure made of stones or branches and then the shepherd would lay down across the opening and the shepherd would literally be the door. Jesus is the door of the kingdom you can't get in except through him.
Salvation is like coming home.
Do you remember the story of the prodigal son. He finally came to his senses. I've got to get back to dad's house. Coming home means at last I'm where I belong, where I'm comfortable. We were created to be in fellowship with God and many people when they finally accept the Lord they feel like they have come home.