RENEWAL OF THE MIND
A Christian's spiritual struggle is not waged against any earthly opponent, but against the spiritual evil that fills the world. The Bible refers to these evil spiritual forces as "principalities and powers." In Scripture, Satan is characterized as the “accuser of the brethren”: (Rev.12:10), our “adversary”(I Pet. 5: 8), “the devil” (Matt. 4:1), our “enemy”(Matt. 13:39), the “evil one” (I Jn. 5:19), the “father of lies” (Jn. 8:44), a “murder”(Jn. 8:44), a “roaring Lion seeking to devour us,”(I Pet. 5:8,9), and the “tempter”(Matt. 4:3).
TRANSFORMED RENEWAL OF THE MIND
Salvation is a spiritual change and will bring a renewal of the human mind.’ "be transformed by the renewing of your mind," (Rom. 12:2).

“And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God,” (Rom. 12:2).

[And be not conformed] the word rendered "conformed" properly means to put on the form, fashion, or appearance of another. It may refer to anything pertaining to the habit, manner, dress, style of living, etc., of others.

[Of this world] too aiooni toutoo…The word which is commonly rendered "world," when applied to the material universe, is kosmos, "cosmos." The word used here properly denotes an age, or generation of people. It may denote a particular generation, or it may be applied to the race. It is sometimes used in each of these senses. Thus, here it may mean that Christians should not conform to the maxims, habits, feelings, etc., of a wicked, luxurious, and idolatrous age, but should be conformed solely to the precepts and laws of the gospel; or the same principle may be extended to every age, and the direction may be, that Christians should not conform to the prevailing habits, style, and manners of the world, the people who know not God. They are to be governed by the laws of the Bible; to fashion their lives after the example of Christ; and to form themselves by principles different from those which prevail in the world. In the application of this rule there is much difficulty. Many may think that they are not conformed to the world, while they can easily perceive that their neighbor is. They indulge in many things which others may think to be conformity to the world, and are opposed to many things which others think innocent. The design of this passage is doubtless to produce a spirit that should not find pleasure in the pomp and vanity of the World; and which will regard all vain amusements and gaieties with disgust, and lead the mind to find pleasure in better things.

[Be ye transformed] The word from which the expression here is derived means "form, habit."

The direction is, "put on another form, and change the form of the world for that of Christianity." This word would properly refer to the external appearance, but the expression which the apostle immediately uses, "renewing of the mind,." shows that he did not intend to use it with reference to that only, but to the charge of the whole man. The meaning is, do not cherish a spirit. Devoted to the world, following its vain fashions and pleasures, but cultivate a spirit attached to God, and his.

[By the renewing] By the making new; the changing into new views and feelings The Christian is often represented as a new creature; (II Cor. 5:17); (Gal. 6:15); (Eph. 4:24); (I Pet. 2:2).

TRANSLATED MIND
[Your mind] The word translated "mind" properly denotes intellect, as distinguished from the will and affections. But here it seems to be used as applicable to the whole spirit as distinguished from the body, including the understanding, will, and affections. As if he had said, let not this change appertain to the body only, but to the soul. Let it not be a mere external conformity, but let it have its seat in the spirit. All external changes, if the mind was not changed, would be useless, or would be hypocrisy. Christianity seeks to reign in the soul ....