'Born again' in the Bible

The one who says he is in the Light [in consistent fellowship with Christ] and yet habitually hates (works against) his brother [in Christ] is in the darkness until now.

Everyone who believes [with a deep, abiding trust in the fact] that Jesus is the Christ (the Messiah, the Anointed) is born of God [that is, reborn from above—spiritually transformed, renewed, and set apart for His purpose], and everyone who loves the Father also loves the child born of Him.