2 Corinthians 5:17:

Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.

See also:

Who You Are and What You Have
You’re Dead!
What Romans 8:11 Really Means
Conformed to Christ’s Image
Objection: By Jesus’ Stripes We Were Spiritually, Not Physically, Healed