Holiness is the condition of being holy. It is a quality of life. It is not a church nor a denomination, although some churches or denominations have included the word in their name. Sometimes the name accurately describes a person or a church and sometimes it does not.
We may ask: "How can a sinner, an unholy human being become holy?" Secondly, "How can he remain holy after becoming holy, in an unholy environment, subject to so many temptations?"
First, a sinful human being can neither become holy nor remain that way short of a miracle of God. But, "With God all things are possible" (Mark 9:23). Furthermore, it is required by God's commandment in 1 Peter 1:13-19 and other places.
The first part of the miracle takes place when a sinner acknowledges that he is a sinner and in faith and repentance comes to Jesus Christ in prayer. He then receives God's gift of salvation, eternal life, spiritual life, through Jesus Christ our Lord (Romans 6:23). When this happens he becomes a "new creature; old things are passed away; all things are become new" (2 Corinthians 5:17). With this comes a hunger for spiritual food from the Word of God, the Bible and a spiritual power inside to enable him to overcome temptation and sin. God imparts the Holy Spirit and a new nature.
The second part of the miracle takes place as "God works in you, both to will and to do of his good pleasure" (Philippians 1:13). And when you, by an act of your will, begin to do what it says in Romans, chapter 6, and you begin to "put off' the old man and sins of the flesh by God's help and grace, as described in Ephesians 4:17-32 and 1 Timothy 6:5, and as you begin to "put on the new man which after God is created in righteousness and true holiness," as is described in Ephesians 4:24, Colossians 3:10, and Romans 13:14.
You will find this miracle can begin to happen in your life.
You can obey this command to be holy. Without it, you won't make into God's holy heaven, and if you were to reach there in a sinful or unholy state, you wouldn't feel comfortable there. Now is the time to prepare yourself for that prepared, holy place.
You will find that when God works inside of you, it will affect all areas of your life. God said that we should "perfect holiness in the fear of the Lord." It will affect your speech, your pleasures, your attitudes, the places you go, the activities in which you participate, and even the clothes you wear, as well as how you spend your money.