Ephesians 4:24
and to put on the new self, created after the likeness of God in true righteousness and holiness.

The new self is unlike the old which, has passed away and is gone (2 Cor 5:17 The old has passed away;), is corrupt through its deceitful desires (Ephesians 4:22 … your old self, which belongs to your former manner of life and is corrupt through deceitful desires,) and from which nothing good can come. It had to be taken out, gotten rid off because it was irredeemable. Your former manner of life needed to be put away.  It is the new self alone that has been created after the likeness of God in true righteousness and holiness that can and is able to please God. The old you is utterly incapable of pleasing God. Romans 8:6 – 8
For to set the mind on the flesh is death, but to set the mind on the Spirit is life and peace. For the mind that is set on the flesh is hostile to God, for it does not submit to God’s law; indeed, it cannot. Those who are in the flesh (old, fallen nature/self) cannot please God.

Your former manner of life represents your old self.  Remaining in the old self is a dead end; it is enmity with God, as it cannot submit to God’s law and therefore is utterly incapable of pleasing God.

If you insist on your former manner of life transformation is impossible, the Christian life is impossible to hack. 

It is impossible to hack this new life, to please God in the old mode, if you insist on staying your mind on things that gratify and pacify, satisfy and magnify the flesh, the old self that is corrupt and whose corruption is expressed through its deceitful desires. If all I dwell in my mind is how to please the flesh/fallen nature, I’m not going to ever be right with God. The fallen nature that I am nursing and indulging does not have the inherent capability to ever be right with God – it is beyond redemption. It can never please God. It is impossible to walk in the flesh (dwelling on, living in and gratifying its desires) and maintain righteousness or be right with God. Hence the need for it to be taken out, for us to be born again or regenerated.

Regeneration is instantaneous (John 5:24, Luke 23:43). However, transformation is a lifelong process, a journey we embark on once we experience the new birth. It is this path of transformation (AKA discipleship) you need to diligently travel on. God has done his part in giving you new life – which you could never have done – by “the washing of regeneration and renewal of the Holy Spirit, (Titus 3:5) “not because of works done by us in righteousness, but according to his own mercy,” (Titus 3:5). Thereafter, it is primarily your responsibility to attend to your new self, to work on the renewal of your mind for transformation.

Our minds have to be rewired in the ways of the new self which is created “after the likeness of God in true righteousness and holiness”(Eph 4:24). This transformation into the likeness of God in our own lives requires a revolution in our thinking and reasoning faculties that now have to be aligned with the truth of God.

If you do not submit your thought life and process to the authority of scripture, if your reasoning remains unaffected by the truth of the gospel, you will never experience personal transformation. Where our thought life runs wild and unchecked by God’s word, it is impossible to please God. In fact, we’re on a one-way street, a collision course with Him. (Romans 8:6 – 8)

Your mind is, quite literally, where the battle is right now. It is the battle for your mind that you need to win. Whoever or whatever wins the battle for your mind has won you. And your mind will tend to dwell on, gravitate towards the things you expose it to. This is a natural law. If you feed your mind the things above it will naturally gravitate towards the things above. If you feed it the things of the flesh, it’ll dwell on the desires and passions of the flesh. It is like a formula – the output is purely reliant on the input. In other words, you reap what you sow. Nothing more, nothing less. Galatians 6:7-8
“Do not be deceived: God is not mocked, for whatever one sows, that will he also reap. For the one who sows to his own flesh will from the flesh reap corruption, but the one who sows to the Spirit will from the Spirit reap eternal life.”

Furthermore, you can and are able to (and it is totally within your reach and choice) to intentionally dwell on the things above through meditation and study of God’s word.

You can, and are called by God, to be intentional and targeted in this matter. You see, the more we engage in the spiritual things the greater the chance, not only for our mind to be captivated by it but also for us to be genuine fruit-yielding folk – like those who respond to the word correctly and are not just mere listeners as in the parable of the sower (Mark 4:1 – 8). Whilst persistently dwelling on the flesh (its interests and desires thereof) results in death, choosing to focus your mind on the things of the Spirit, choosing to set your mind on the things above empowers one for victorious living.

It is in keeping your mind preoccupied and exercising it with God’s word that you will experience personal victory in your own life.