The mind is an amazing creation of God. In Romans 12:2, the Bible says to be transformed by the renewing of your mind. Mind renewal is an act of the will. 1 Peter 1:13 says to gird (prepare) your mind for action. That means to tie it down. The mind is like a two-year-old child, it need close supervision, otherwise, it will end up in enemy territory. A wondering mind simply creates doubt, confusion and instability.
In 1 Corinthians 14:33, Paul writes, “For God is not a God confusion but of peace…” , and in James 1:8 the doubting man is portrayed as “a double-minded man, unstable in all of his ways.” Both words, “confusion” and “unstable,” come from the same Greek root word which means “instability, a state of disorder, disturbance, confusion”. This description of double-mindedness and confusion, which is not from God closely, resembles the chaos, which Dr. Dan Siegel describes as a result of dis-integration of the mind. The opposite of a dis-integrated mind is a peaceful and coherent mind.
In Philippians 4:4-9, Paul writes a prescription for an integrated mind that produce a sense of well-being for the believer.
Rejoice in the Lord always. I will say it again: Rejoice! Let your gentleness be evident to all. The Lord is near. Do not be anxious about anything, but in everything, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus. Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things. Whatever you have learned or received or heard from me, or seen in me—put it into practice. And the God of peace will be with you.
The focus of the Greek word for “guard” in this passage is that of a military sentinel while “heart” is “the seat of the desires, feelings, affections, passions, [and] impulses” and “mind” refers to “the thoughts which proceed from the heart of Christians”. In essence, Paul links a person’s thinking with well-being and promises that thinking on “these things” will provide protective custody for both the heart and the mind. Interestingly, neuroscience is beginning to understand the physical changes that take place in the brain of a believer who thinks “on these things” bringing about not just spiritual transformation but the “renewing of the mind” found in Romans 12:2.