As he which hath called you is holy, so be ye holy in all manner of conversation; because it is written, Be ye holy; for I am holy. —1 Peter 1:15-16
You cannot study the Bible diligently and earnestly without being struck by an obvious fact—the whole matter of personal holiness is highly important to God!
Neither do you have to give long study to the attitudes of modern Christian believers to discern that by and large we consider the expression of true Christian holiness to be just a matter of personal option: “I have looked it over and considered it, but I don’t buy it!”
I have always liked the word exhort better than command so I remind you that Peter has given every Christian a forceful exhortation to holiness of life and conversation. He clearly bases this exhortation on two great facts—first, the character of God, and second, the command of God. ICH061-062
[In the New Testament] the emphasis is not upon happiness but upon holiness. God is more concerned with the state of people’s hearts than with the state of their feelings. OGM049
Tozer on the Holy Spirit.