Generally, the word “holiness” describes something that is considered sacred, godly, or spiritual. In the Jewish Scriptures (Old Testament), the words for holiness have more specific meanings. One meaning emphasizes the difference between what is holy or sacred and what is considered ordinary or ritually unclean (Ezek 22:8). Holy people (Israel’s priests) and holy things (priests’ clothes; sacrifices) were not to come into contact with ordinary people or things. The holy things could become impure (no longer holy or acceptable to the Lord), and that person could be harmed.

Another meaning for holiness has to do with “setting apart” or “dedicating” something for a special purpose. Things or people were to be dedicated or set apart for complete destruction as a holy gift for the Lord (Lev 27:28; Josh 6:15—7:13). People were also chosen for special duties or for holy purposes. Israel’s priests were chosen and set apart for doing the sacred work in the temple. People known as Nazirites took vows of holiness, which meant that they would act in a certain way or do certain things that set them apart from other people (Num 6:1-21). Before giving the Israelite people the Law that would set them apart from other people, the Lord told Moses that he had chosen Israel to be his holy nation (Exod 19:5,6; see also Isa 43:21). One New Testament writer uses these same words in describing Christ’s followers on earth (1 Pet 2:9).

Things connected to the Lord or the Lord’s presence are considered holy. For example, the Lord was said to live in the most holy place in the temple located on Mount Zion in Jerusalem. For this reason Jerusalem was called the “holy city” and Zion was called the Lord’s “holy mountain.” The Lord is often referred to as the “Holy God of Israel,” meaning God is “set apart from human beings and awesome” but is also Israel’s personal God, who chose them (Isa 41:8,9) and lives among them (Exod 25:18-22; 1 Kgs 8:6-13; Isa 6:1-8). Often in the Old Testament the holy and awe-inspiring Lord appears in fire or a cloud, a sign of either the Lord’s protection or his judgment (Exod 3:2,3; 19:18; Deut 5:22-27; Isa 4:4; Ezek 1:4-28). The Lord’s fire is also said to purify in the same way a hot fire is used to make a precious metal more pure (see Ezek 22:18-22). And those who survive the Lord’s “fiery anger” are seen as the ones who are holy or chosen to live holy lives.

In the New Testament, the Holy Spirit is given to those who believe in Jesus. The Spirit both teaches and guides (Rom 15:13-16; 1 Cor 2:13), making it possible for the followers of Jesus to live holy lives and be holy, just as God is holy (Gal 5:16-25; 1 Pet 1:16). The Law and many of Israel’s prophets emphasized that holiness came from living according to the Lord’s commands. The New Testament writers also recognize the holiness of God’s Law, but for them holiness is not based on following the rituals connected to worship at the temple. Instead, holiness comes from the presence of God’s Spirit living among Christ’s followers, the church (see Eph 2:19-22; 1 Pet 2:4,5).