How do we know if we have truly experienced the spiritual reality of new birth? How do I know if God has acted on my life? This is such a critical question in our lives, and John Piper addressed it in a 2007 Christmas sermon:
“Whoever has the Son has life; whoever does not have the Son of God does not have life.”
John 1:14, John 1.16″>16, “The Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth. And from his fullness we have all received grace upon grace.” That is where our life comes from. The Son, the Word made flesh, is our life. This is the testimony.
How do you know that you are a child of God? Well, how do I know that John Piper is alive? Is it my birth certificate? Does anybody believe you are alive because you have on file a birth certificate? You don’t. It is because you breathe.
It is exactly the same with Jesus Christ. You know that you are a child of God because you breathe. You are alive. You see him for who he is. You love him for who he is. You trust him for who he is. You embrace him for who he is. That is how you know you are alive. The testimony is within you. And what is it again—the testimony? 1 John 5.11″>First John 5:11, “And this is the testimony, that God gave us eternal life.” That is how you know. You are alive to him—alive to God—and dying to sin.
The aim of the new birth is to awaken faith in the crucified, incarnate Son of God. And if there were no incarnate, crucified Son of God, then the new birth would not be performed, because the point of it would not be possible. The incarnation of the Son of God is necessary because the life that we have in the new birth in union with him is the life of the Son, the incarnate Christ.
I come now to close with justification and purification. Or if you want to use the old sanctification, you can. But purity is what you use in this text. I am going to use it. 1 John 3.4–5″>First John 3:4–5, “And everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness. You know that he appeared in order to take away sins, and in him there is no sin.”