Man does not change in order to be saved, but true salvation always brings about an evident change in the life of the new believer. Perhaps the change is less noticeable in some new believers and more noticeable in others; however, no change means no salvation. The change is not always an immediate outward change because it involves a change of the inward nature. A person who trusts Christ for salvation becomes a new creature (Galatians 6:15). It might be best to consider how this could be likened to a dog (Matthew 15:26-27) becoming a sheep (John 10:16). A new man now dwells within the new Christian to help combat and defeat the old sinful nature (Ephesians 4:22-24). Salvation is not merely the turning over of a new leaf; it is a new birth (John 3:3) where one is passed from spiritual death to spiritual life (John 5:24).
If asked concerning the origin of thoughts, the average person would swiftly respond with “the mind” or some similar answer. This is not, however, the emphasis of scripture. Overwhelmingly, scripture indicates that thoughts proceed from the heart. This does not mean the beating organ within one’s chest since the scriptures use “heart” in a different manner. When God brought judgment in the days of Noah, He saw that the thoughts of man’s “heart was only evil continually” (Genesis 6:5). In Matthew 15:19, the Bible says, “For out of the heart proceed evil thoughts.” In Luke 24:38, the Lord Jesus asked the disciples, “why do thoughts arise in your hearts?” When one’s thoughts are not according to God’s will, it is a matter of the heart not being right with God.