Recently someone reached out asking for a simple explanation of what it means to be “born again.”
Blessed be the God and Father of our Lord Jesus Christ! According to his great mercy, he has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead.
1 Peter 1:3 ESV
The idea of being “born again” is something that the Bible speaks about using a variety of terms, such as: Receiving a new heart, becoming a new creation, being made alive in Christ.
The exact phrase, “born again” is something which Jesus used when speaking to a man named Nicodemus: a moral, religious man who was well-respected in his community. Nicodemus came to Jesus asking for the essence of Jesus’ teaching, and Jesus told him: “Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God.” (John 3:3)
What this means is that although we are born physically alive, every person’s default condition is that they are spiritually dead and disconnected from God.
God loves us, and yet: we are sinners, both by nature and by choice, and as a result there is a separation between us and God, and our default condition is that we are spiritually dead rather than alive.
There are a lot of people in the world who are like Nicodemus: moral and “good” people. And yet, Jesus told this moral man that he needed to be born again. And this is the message of Jesus to all of us as well: “YOU need to be born again!” Not just everyone else; not just the drunks and the immoral people, but YOU too!
YOU need to be born again by coming into a relationship with God by faith in Jesus Christ: faith in the fact that he died in your place to reconcile you to God by imputing his righteousness to you, and imputing your sins to him; faith that he rose from the dead to give you the hope and promise of eternal life!
When you are born again you receive:
- a NEW HEART: The very essence of who you are changes! You receive a new heart, with new desires.
- a NEW IDENTITY: You change from being an enemy of God to being a child of God.
- a NEW MIND: You begin to think differently.
- NEW EMOTIONS: You feel differently; God pours out his love, joy, and peace into your heart.
- A NEW COMMUNITY: You become part of the people of God, those who are being saved.
- A NEW POWER: Power over sin; we are no longer slaves to our flesh, but we gain the power to be free when we are born again by putting our faith in Jesus and God places his Spirit inside of you to strengthen you in your weakness.
Here is an audio version of this, a clip from a sermon titled: The Power and Purpose of the Resurrection (click here for entire sermon):
Theology for the People 
We just talked about what defines a Christian in our home group. I think this is related in many ways to your post. How would you answer this question (short format)?
A Christian is someone who believes in Jesus. To believe in Jesus means to trust in, rely on, cling to, and adhere to Him – in his person, teachings, and actions.