Repentance of Both the Mind and Soul
1 John 3:1–10 NET

See what sort of love the Father has given to us: that we should be called God's children — and indeed we are! For this reason the world does not know us: because it did not know him.

2 Dear friends, we are God's children now, and what we will be has not yet been revealed. We know that whenever it is revealed we will be like him, because we will see him just as he is.

3 And everyone who has this hope focused on him purifies himself, just as Jesus is pure).

 

4 Everyone who practices sin also practices lawlessness; indeed, sin is lawlessness.

5 And you know that Jesus was revealed to take away sins, and in him there is no sin.

6 Everyone who resides in him does not sin; everyone who sins has neither seen him nor known him.

7 Little children, let no one deceive you: The one who practices righteousness is righteous, just as Jesus is righteous.

8 The one who practices sin is of the devil, because the devil has been sinning from the beginning. For this purpose the Son of God was revealed: to destroy the works of the devil.

9 Everyone who has been fathered by God does not practice sin, because God's seed resides in him, and thus he is not able to sin, because he has been fathered by God.

10 By this the children of God and the children of the devil are revealed: Everyone who does not practice righteousness — the one who does not love his fellow Christian — is not of God.

A lot is said about repentance being a change of mind, a mental thing.
Jesus and His apostles speak about a double kind of repentance.
Yes a repentance of the mind - to think again,
Romans 2:4 NET

Or do you have contempt for the wealth of his kindness, forbearance, and patience, and yet do not know that God's kindness leads you to repentance?

but as important — the repentance of the soul.
2 Corinthians 7:9–10 NET

Now I rejoice, not because you were made sad, but because you were made sad to the point of repentance. For you were made sad as God intended, so that you were not harmed in any way by us.

10 For sadness as intended by God produces a repentance that leads to salvation, leaving no regret, but worldly sadness brings about death.

In our New Testaments that is, in the language it was written, Metanoia — Metanoia a change of mind, metameleia — metameleia change of soul.

Page 711, Repentance

In a sense the repentance of the mind and focusing on that alone can lead to a technical approach which makes the idea of just giving lip service to important things easy.
And God always condemns mere lip service to His word and ways.
Matthew 15:8–9    NET

“This people honors me with their lips, but their heart is far from me, 

9 and they worship me in vain, teaching as doctrines the commandments of men.”

Repentance of the heart, the soul, is a real changing of our yearnings, of our aspirations, of our affections and love.
God calls love of the wrong things idolatry, as it takes that place in our hearts that is to be reserved for Him alone.
In idolatry we worship the created thing, instead of the Creator Who is to be forever praised!
Our hearts are to be filled with His love
Our hearts are to be filled with His love, not love for this world or anything in it.
Filled with His love, out flowing to—
For that to happen we need the repentance of our soul. The deep working of His Holy Spirit Who we must not refuse or oppose or grieve.
We need to seek, even earnestly crave, that God might reveal Himself to us in all His glory, wonder and power; and perceive His righteousness and truth. Then we can be filled with awe and be separated from evil, finding His love and forgiveness in all of His bountiful mercies and grace.
What does this mean for our lives?
We must be real with God and each other.
With out repentance there is no forgiveness of sins, and the blood and body Jesus gave to His Heavenly Father for your forgiveness in dying on the cross, will not apply to you if there is no real repentance before God.
Luke 24:45–47    NET

Then he opened their minds so they could understand the scriptures,

46 and said to them, “Thus it stands written that the Christ would suffer and would rise from the dead on the third day,

47 and repentance for the forgiveness of sins would be proclaimed in his name to all nations, beginning from Jerusalem. ...”

When turning away from sin and evil behaviour (separating ourselves form the world, and to the Lord Jesus — becoming 'holy'), it must be with all of our heart, all of our soul, all of our mind, and all of our strength (body).
And we must turn to, and do, what is right in the same way ...
Mark 12:29–31 NET

Jesus answered, “The most important is: ‘Listen, Israel, the Lord our God, the Lord is one.

30 Love the Lord your God with all your heart, with all your soul, with all your mind, and with all your strength.’

31 The second is: ‘Love your neighbor as yourself.’ There is no other commandment greater than these.”

The Lord made us as body, soul, and spirit, and calls us to recognise that in fully having true and loving holy relationships with Him and each other in Spirit and in truth!
And that starts with a full and true repentance — not just one part of our life or make up, but of all of us, to His Glory, and our Eternal Reward!
[being edited 2011-09-02] \dots