1 Peter 1 14-16
As people who obey God, do not let yourselves be shaped by the evil desires you used to have when you were still ignorant. On the contrary, following the Holy One who called you, become holy yourselves in your entire way of life; since the Tanakh says,
“You are to be holy because I am holy.”
Holiness essentially defines the Christians new nature and conduct in contrast with their pre-salvation lifestyle. The reason for practicing a holy manner of living is that Christians are associated with the holy God and must treat Him and His Word with respect and reverence. We therefore glorify Him best by being like Him.