1 Corinthians 6:17:

But he that is joined to the Lord is one spirit.

See also:

Who You Are and What You Have
What Romans 8:9 Really Means
Does Faith Come from Your Spirit, Your Mind or Somewhere Else?
Is It Technically Incorrect to Say That Jesus Still Heals Today?
Do We Already Have Healing in Our Born-Again Spirits?
Objection: Faith Preachers Embrace Mormon-Like Teaching That We Can Become Gods, or Are “Little Gods” Already, So They Are Evil Cultists