Our old life, previously dead to God because of sin, is buried, and we are raised “to walk in newness of life” with Him (Romans 6:4). Christ gives us a completely new and holy nature and an incorruptible life.
It is “dead in trespasses and sins” (Ephesians 2:1) and can only be made alive by a supernatural awakening, which happens when we come to Christ and are indwelt by Him. The old nature is dead to the things of the Spirit and cannot revive itself. These are actions the old nature is incapable of doing or even desiring to do.
The new nature fellowships with God, obeys His will, and is devoted to His service. In Christ, we are regenerated, renewed, and born again, and this new creation is spiritually minded, whereas the old nature is carnally minded.