Sound mind Peaceful mind

Reference Scripture:

For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind. (II Timothy 1:7)

Sound mind = *StrongsGreek*]4995σωφρονισμός swfronismovs sophronismos {so-fron-is-mos'}from 4994; discipline, i.e. self-control:--

What is a “sound mind” according to the scripture?

The firsts thoughts go to one being mentally stable, reasonable and logical decision making, not emotional.
 

He that hath no rule over his own spirit is like a city that is broken down, and without walls. (Proverbs 25:28)

Yeshua has given us the ability to control our spirit/mind, thoughts and emotions.  Be careful what you say.  As a Saint, controlling your tongue is vital to your spiritual health and life.

Here is a warning to be conscience of the effects of medicine on the brain that should not bleed over to your mind.  Most medicines that have been developed by man has side effects.  Natural medicinal herbs and some foods have strong effects on the brain. There is a chemical reaction, the psychologist call it neuroticism for neurological damage caused by exposure to too many natural or manufactured toxins.  The brain gets drunk with chemicals especially after long term indulgence. It affects your thinking.

Spiritually,  evil influences invade the unprotected mind.  The enemy constantly bombards the eyes and ears with evils and they slowly affect some individuals and it seeps into the  spirit.  The brain registers them, your spirit must rebuke them. Remember Lot, his soul was vexed.  "And delivered just Lot, vexed with the filthy conversation of the wicked: (For that righteous man dwelling among them, in seeing and hearing, vexed his righteous soul from day to day with their unlawful deeds;)" (II Peter 2:7-8)

Vexed = [*StrongsGreek*] 2669καταπονέω kataponevw kataponeo {kat-ap-on-eh'-o}from 2596 and a derivative of 4192; to labor down, i.e. wear with toil (figuratively, harass):--oppress, vex.

Letting your sinful nature control your mind leads to death.  But letting the Spirit control your mind leads to life and peace.”  (Romans 8:1–6) The Holy Spirit controls your spirit, your spirit is your mind  and your spirit/mind is to control your brain and not the other way around.  Contrary to carelessness or seared conscience which is a result on impenitence. The sinful nature is having a carnal mind. A mind at war and not peace. For to be carnally minded is death; but to be spiritually minded is life and peace. (Romans 8:6) The battle between the flesh and the Spirit is real within the Saints psyche but Yeshua has given us the victory.

Carnal = [*StrongsGreek*] 4561σάρξsavrx sarx {sarx}probably from the base of 4563; flesh (as stripped of the skin), i.e. (strictly) the meat of an animal (as food), or (by extension) the body (as opposed to the soul (or spirit), or as the symbol of what is external, or as the means of kindred), or (by implication) human nature (with its frailties (physically or morally) and passions), or (specially), a human being (as such):--carnal(-ly, + -ly minded), flesh(-ly)

Yeshua gave us peace, a peaceful mind a peaceful spirit. He gave us double peace. "Peace I leave with you, my peace I give unto you: not as the world giveth, give I unto you. Let not your heart be troubled, neither let it be afraid. "(John 14:27)  No trouble in or with the mind comes with the Peace of Yeshua! "Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee. Trust ye in the LORD for ever: for in the LORD JEHOVAH is everlasting strength: "(Isaiah 26:3-4)

YHWH has done many great things for us in delivering us from sin and death.  He has given us weapons to fight against a defeated enemy, he has given us spiritual power and authority over the earth and the enemy.  He has given us liberty and placed us above the rudiments of the earth but it seems that some Saints sometimes  don’t acknowledge or believe that.  Some are not aware because they don’t hear the Holy Spirit with an understanding but those who know should walk in the victory that Yeshua gave us.  This is why he told us to pray without ceasing, this is why Paul warned us and revealed to us the tactics of the enemy.  Yeshua redeemed us from evil, mind, body and spirit, take control of yourself in the name of Yeshua.