Since therefore Christ suffered in the flesh, arm yourselves with the same way of thinking, for whoever has suffered in the flesh has ceased from sin, so as to live for the rest of the time in the flesh no longer for human passions but for the will of God. 1 Peter 4:1–2, ESV
Even though genuine Christians are new creations and have been purchased out of the world through the redemptive work of Christ on the Cross, as they attempt to live godly lives in the temporal, they will come under tremendous pressure to compromise by reverting back to the fleshly way of dealing with life. This way of reacting to circumstances, both good and bad, has emotions as its catalyst motivated by a form of self-righteousness that is manifested through self-exaltation and self-protection.
Here we witness ourselves reacting to the good and bad in a way that is little different than we did prior to our salvation. We may even attempt to justify our actions by proclaiming that we are only seeking justice. Pride is the culprit behind this and when we stumble into these sins it is because we are not spirit-filled and, therefore, not humble.