On Reforming Ourselves
Be not conformed to this world, but be reformed in the newness of your mind, that you may prove what is the good, and the acceptable, and the perfect will of God. –Romans 12:2
1. What is forbidden is the forming of oneself after the pattern of the world. Be not conformed to this world, that is, to the things which pass away with time. For this present world is a kind of measure of those things which pass away with time. A man forms himself after the pattern of things transitory when, willingly and lovingly, he gives himself to serve them. Those also form themselves after that pattern who imitate the lives of the worldly, This then I say and testify in the Lord: That henceforward you walk not as also the Gentiles walk in the vanity of their mind (Ephesians 4:17).
2. We are bidden to undertake a reformation of the interior man when it is said, But be reformed in the newness of your mind. By mind is here meant the reason, considered as the faculty by which man makes judgments about what he ought to do. In man, as God first created him, this faculty existed in all the completeness and vigour it could need. Holy Scripture tells us of our first parents that God filled their hearts with wisdom, and shewed them both good and evil (Ecclesiastes 17:6). But through sin this faculty declined in power and, as it were, grew old, losing its beauty and its brilliance.
The Apostle warns us to form ourselves again, that is, to recover that completeness and distinction of mind that once was ours. This can indeed be regained by the grace of the Holy Ghost, and we should therefore use every endeavour to share in that grace—those who lack that grace that they may obtain it, and those who already have gained it faithfully to progress and persevere. Be renewed in the spirit of your mind, says St. Paul (Ephesians 4:23). Or again, in another sense, be renewed in your external actions, that is to say, in the newness of your mind, i.e., according to the new thing, grace, which you have internally received.
3. The reason for this warning is that you may prove what is the will of God. We know what befalls a man whose sense of taste suffers in an illness, how he ceases to have a true judgment of flavours and begins to loathe pleasantly-tasting things and to crave for what is loathsome. So it is with the man whose inclinations are corrupted from his conforming himself to the things of this world. He has no longer a true judgment where what is good for him is concerned. It is only the man whose inclinations are healthy and well directed, whose mind is made new again by grace, who can truly judge what is good and what is not. Therefore on this account is it written, Be not conformed to this world, but be reformed in the newness of your mind that you may prove, that is, that you may know by experience. As again it says in the psalm, Taste and see that the Lord is sweet (Psalm 33:9).
What is the will of God: that is, to say the will by which he wills us to be saved. This is the will of God your sanctification (1 Thessalonians 4:3).
The will of God is good, because God wills that we should will to do what is good, and He leads us to this through His commandments. I will shew thee, O man, what is good, and what the Lord requireth of thee (Micah 6:8).
The will of God is agreeable in as much as to him who is rightly ordered it is a pleasure to do what God wills us to do.
Nor is the will of God merely useful as a means to achieve our destiny, it is a link joining us with our destiny and in that respect it is perfect.
Such then is the will of God as those experience it who are not formed after the pattern of this world, but are formed over again in the newness of their minds. As to those who remain in the old staleness, fashioned after the world, they judge the will of God not to be a good but a burden and useless. (In Romans 12)
Hebrews 11: 1-7
Psalm 145: 2-5, 10-11
Mark 9: 2-13