Jesus calls this spiritual birth being "born again." We all have a physical birthday, but not all of us have a spiritual birthday, which comes when we accept God's invitation to trust in Christ as Lord and Savior. With no spiritual birth, we die twice--physically and spiritually. But, with a spiritual birth, we die just once (physically), for our spirit lives forever.
Born once, we die twice. Born twice, we die once.
If we're born twice, we're saved from spiritual death and we're in the family of God forever.
3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except one be born anew, he cannot see the kingdom of God.