There are several Hebrew words for holiness in the Tanakh/Old Testament. For the scriptures below, qodesh and qadowsh are used. Qodesh
{ko'-desh} means a sacred place or thing; rarely abstract, sanctity:--consecrated (thing), dedicated (thing), hallowed (thing), holiness, (X most) holy (X day, portion, thing), saint, sanctuary. Qadowsh
{kaw-doshe'} or qadosh {kaw-doshe'}; means sacred (ceremonially or morally); (as noun) God (by eminence), an angel, a saint, a sanctuary:--holy (One), saint. From the New Testament we will be using hagios
{hag'-ee-os} which means sacred (physically, pure, morally blameless or religious, ceremonially, consecrated):--(most) holy (one, thing), saint. Another definition is hagiasmos
{hag-ee-as-mos}. It means properly, purification, i.e. (the state) purity; concretely (by Hebraism) a purifier:--holiness, sanctification. Holiness is being set apart for the glory and will of God. To be holy is one of the essential elements of God's requirements to those He has called.
Leviticus 11:43-45: Ye shall not make yourselves abominable with any creeping thing that creeps, neither shall ye make yourselves unclean with them, that ye should be defiled thereby. For I am the LORD your God: ye shall therefore sanctify yourselves, and ye shall be holy; for I am holy: neither shall ye defile yourselves with any manner of creeping thing that creeps upon the earth. For I am the LORD that brought you up out of the land of Egypt, to be your God: ye shall therefore be holy, for I am holy.
Isaiah 62:12 And they shall call them, The holy people, The redeemed of the LORD: and thou shalt be called, Sought out, A city not forsaken.
Romans 12:1-2: I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.
Ephesians 1:3-4: Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ: According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love:
1 Thessalonians 4:7:For God hath not called us unto uncleanness, but unto holiness.
1 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.
2 Peter 3:11: Seeing then that all these things shall be dissolved, what manner of persons ought ye to be in all holy conversation and godliness,
Revelation 22:11: He that is unjust, let him be unjust still: and he which is filthy, let him be filthy still: and he that is righteous, let him be righteous still: and he that is holy, let him be holy still.