Ephesians 4: 22-24

You were taught, with regard to your former way of life, to put off your old self, which is being corrupted by its deceitful desires; to be made new in the attitude of your minds; and to put on the new self, created to be like God in true righteousness and holiness

It doesn't take much in a day to see the corrupt sinful nature in us
Paul knew it, and knew that it wasn't a simple thing that you can just decide one day to stop sinning and live for God
Even with the strongest will and faith it will be impossible to keep from your "old self" if you are not following this word of God
It seems obvious now but I have so often missed the two parts to this passage
I get the whole "putting off of the old self" meaning getting rid of temptations and keeping myself from sin, but the second part is just as important and even more so..
"Putting on the new self"
Our new self with is created to be like God in true righteousness and holiness is the complete opposite of the sinful nature within us, and if I am ever to keep myself from sin and follow God I must be putting on my new self
What is this "new self"? Well Paul talks about this all throughout the book of Ephesians.. it's about being unified in the body of Christ, being loving and kind to everyone, and humbly walking with God
This is the righteousness and holiness that God has originally purposed us for
So as I call myself a Christ and desire to live that way..
Am I living according to my sinful nature
or Am I living according to my new self in true righteousness and holiness the way God has purposed me to