Put to death, therefore, what is in you.
In the original language, here's literally what it says: what is earthly in you.
He's talking about your
He's talking about those sins that used to you before you knew Christ.
What 'old way of life' sins do you find yourself still tolerating or minimizing? Why have you struggled to put them to death?
How does understanding that you've been 'raised with Christ' change your perspective on dealing with sin?