And be renewed - That is, it is necessary that a man who has been following these should become a new man; see the notes on John 3:3 ff., compare the notes on 2 Corinthians 4:16. The word used here - ἀνανεόω ananeoō - does not occur elsewhere in the New Testament; but it has the same meaning as the word used in 2 Corinthians 4:16, and Colossians 3:10. It means to make new, and is descriptive of the work of regeneration. This was addressed to the church, and to those whom Paul regarded as Christians; and we learn from this:
(1) That it is necessary that man should be “renewed” in order to be saved.
(2) That it is proper to exhort Christians to be renewed. They need renovated strength every day.
(3) That it is a matter of “obligation” to be renewed. People are “bound” thus to be renovated, And,
(4) That they have sufficient natural ability to change from the condition of the old to that of the “new” man, or they could not be exhorted to it.
(See the supplementary Romans 8:7, note; Galatians 5:17, note.)
In the spirit of your mind - In your temper; your heart; your nature.