Holiness is a difficult subject to address. The Apostle Peter said in 1st Peter 1:15-16, "But 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." The word Peter used here is "hagios" (pronounced hag-ee-os) which means, according to Dr. Strong, "...(an awful thing) compare G53, [H2282]; sacred (physically pure, morally blameless or religious, ceremonially consecrated): - (most) holy (one, thing), saint." We are told in verse 15 to be "holy in all manner of conversation..." That word "conversation" is certainly more that just what we say but what we do, e.g., how we behave. Then in verse 16 we are given the reason for being holy because the Bible says God is, "holy." I am made to think of that old chorus we used to sing in church;
O to be like Thee! O to be like Thee,
Blessed Redeemer, pure as Thou art;
Come in Thy sweetness, come in Thy fulness;
Stamp Thine own image deep on my heart.
But what is holiness? Especially old fashioned holiness? The word translated in the King James Version of the Bible is found 611 times. Of those 611 times, 430 are found in the Old Testament while 181 are found in the New Testament. The passage of scripture Apostle Peter quoted in 1st Peter 1:15-16 is probably Leviticus 11:44-45. The Hebrew word here used is qâdôsh qâdôsh (pronounced kaw-doshe', kaw-doshe') "From H6942; sacred (ceremonially or morally); (as noun) God (by eminence), an angel, a saint, a sanctuary: - holy (One), saint." In every instance that the word holiness is used in the Old Testament, it is translated from the Hebrew word. "qôdesh (pronounced ko'-desh ) and has the meaning "...a sacred place or thing; rarely abstractly sanctity: - consecrated (thing), dedicated (thing), hallowed (thing), holiness, (X most) holy (X day, portion, thing), saint, sanctuary."
In the New Testament the word holiness is translated from several different words. Think of the words piety, purity, godly, sacredness, reverent, these are all words that convey the meaning that we call holiness. The word holy however is, except in a few instances, translated from the word found in 1st Peter 1:15-16. It seems evident to me then that we are to be God-like, that is Christ-like in all of our dealings with each other and with an unbelieving world. So then true holiness is to be like Jesus in everything we do. The Apostle Paul said in Colossians 3:17, "And whatsoever ye do in word or deed, do all in the name of the Lord Jesus, giving thanks to God and the Father by him." So if we have "learned Christ..." if we have heard His voice and if we "have been taught by him, as the truth is in Jesus..." that we should "put off concerning the former conversation the old man, which is corrupt according to the deceitful lusts; And be renewed in the spirit of your mind; And that ye put on the new man, which after God is created in righteousness and true holiness."