The Hebrew word kadosh means "set apart". It is usually translated, "holy" or "sanctified". The Greek equivalent is hagios.
Being set apart for God involves certain rules. People cannot simply choose to designate a thing as "set apart" in any way they want; things can only be set apart for God in the ways he has ordained.
Meaning in Ancient Israel
The Tenach describes four ways to be set apart for God.
The first way something can be set apart for God is if God simply declares that the thing is special.
For example, the word kadosh occurs for the first time in scripture when God sets apart Shabbat as different from the other days of the week (Genesis 2:3). God later sets apart the days of Pesach as different from the other days of the year (Exodus 12:16).
Nothing in the Tabernacle or priesthood was set apart simply because God declared it so.
People can be set apart for God in this way. Sometimes this is dramatic, such as the calling to be a prophet, but most people do not experience God asking them to do so many specific things, or to be so isolated from society.
There is no ritual done to things that God declares to be set apart for him. Prophets are not anointed.
Scripture often describes a person's receiving of prophecy as an act of God's Spirit. In the Tenach a person being set apart to prophesy sometimes happens only for a short time or even only once.
God may have plans for people other than the role of prophet. Scripture provides examples of God asking someone to fit into his plans by telling the person where to live, where to travel, what career to have, or if and when to marry. The word vocation is used to describe God making these major decisions for someone. A person's vocation is not necessarily the work and life the person finds most pleasing or natural. Moses never claimed to enjoy shepherding the Israelites. Jeremiah wasn't thrilled about being a prophet. Paul was not talented at public speaking. John the Immerser had doubts about the message he was called to proclaim. Jacob wanted fewer wives than were in God's plans and Solomon wanted more.
The second way something can be set apart for God is to through physical isolation.
Moses was told that the place with the burning bush (which later scripture makes clear refers to all of Mount Sinai) is set-apart ground (Exodus 3:5). The curtain hung up as the final wall of the Tabernacle's innermost room made that innermost room so set apart from the world that entering it would kill even the priests.
There is no specific ritual to set an object or place apart physically, but it is necessary to be specific about borders.
People can also use physical isolation as a way of being set apart. Hermits do this for a long time. Other people only use isolation for a few hours or days, such as those attending a prayer retreat or going to a place of private prayer. As always, only God can declare that a place or a form of isolation counts to make a thing set apart for him. Having a favorite, quiet place to pray might help someone calm the mind and focus on God but it creates no spiritual status unless designated by God.
Leviticus 27 tells us how people can dedicate objects to God, and verses 28 and 29 say these dedicated items become "especially set apart". People cannot be dedicated, for anything living that is dedicated must be killed. (Thus Samuel's mother, who dedicated him as a baby, was following an idea from her own mind and desperation, contrary to Torah.)
The ancient Israelites were told to set apart some items to God. For example, the furnishings of the Tabernacle were anointed with oil and blood and became "especially set apart" tools of worship.
But we are not encouraged to dedicate items to God. The Hebrew word translated "dedicated" is in other contexts translated "cursed". Perhaps the best translation is "doomed". (Notice that when God establishes a choice that can lead to a blessing or a curse either option is a form of becoming set apart for God. Such a situation can be described as devoting ourselves to God willingly or forcing God to set up apart in less pleasant circumstances.)
That items dedicated to God are called "especially set apart" means, among other things, that their status as set apart is contagious and can spread by transmission. Thus whatever touches the Tabernacle's altar become holy (Exodus 29:37). This is merely what altars do: they set things apart for God, so that an animal's death is changed from slaughter to sacrifice. However, being set apart cannot not spread to people by transmission. For example, the Torah tells us multiple times that a criminal who grabs hold of the altar gains no safety or benefit. Aharon was set apart by his ritual of anointing, not by the special clothes he wore.
Since people cannot be dedicated to God in this manner, people are never "especially set apart". No one can make things set apart for God by touch. There are no rituals for people being set apart for God in this manner, since it does not happen.
Yet the rituals for kings and priests were purposefully similar to those for dedicated objects. Kings and priests had more than a vocation: they became tools of God and everything they did, each day, represented and should be with God. For kings and priests God chose more than the "big decisions" of vocation. If they acted contrary to God's specific plans it was at best a waste of time, and at worst a disaster for the entire community. Thus kings and priests were anointed, as tools of God. They could transmit certain spiritual characteristics by touch (as when priests transferring guilt by laying their hands on the heads of animals).
Remembering things can set them apart for God. (In scripture remembering is about prioritization and action, not the opposite of forgetting.)
Remembering God's commandments makes us set apart (Numbers 15:40). Remembering Shabbat keeps it set apart (Exodus 20:8).
People can remember things and people before God, in a way asking that they become set apart to God. Intercessory prayer is simply asking that God actively make his will for someone or something happen when it appears God's will is dormant, or asking for God to honor covenant promises he once proclaimed. Thinking of prayer as remembering things before God helps us understand why only prayer that is aligned with God's plans produces results.
Meaning in the First Century
God's Spirit was understood by first-century Jewish culture to be the channel of God's activity (Matthew 1:20, 3:11). Refusing to give God credit for his activity was understood to reveal an unrepentant heart not ready for forgiveness (Matthew 12:31-32) and perhaps even showing a person who would never repent to receive forgiveness (Mark 3:29).
According to Hebrews 12:14 being set apart is necessary to see God. It should not surprise us that God's Word was further revealed it describes the different kinds of being set apart helping us see God in different ways.
- If we resist our vocation we will not see God "enlarge our boundaries" (First Chronicles 4:10) as he desires.
- If we avoid isolation we will not hear God speak in a "still, small voice" (First Kings 19:12).
- If we shy from our priestly dedication we will not see God "show forth the virtue of him who has called you" (First Peter 2:9).
- If we neglect commemoration of God's plans in prayer, or if we do not "remember from where we have fallen" (Revelation 2:5), then we will seldom see God act in our lives.
Besides elaborating on older understandings of being set apart for God, Yeshua taught something new. Yeshua told his followers that God's Spirit was something set apart that would dwell within them to make them set apart. As Yeshua taught in John 14:16-17:
And I will pray to the Father, and he will give you another Comforter,
that he may abide with you for ever; the Spirit of truth,
whom the world cannot receive because it discerns him not nor knows him,
but you know him for he lives with you and will be in you.
Unlike people with previous types of relationships with God, Yeshua's followers are each "temples" in which God's Spirit dwells (First Corinthians 6:19).
The phrase usually translated "Holy Spirit" only appears three times in the Tenach (Psalm 51:11 and Isaiah 63:10-11). God's Spirit was among the ancient Israelites as a community to instruct them (Nehemiah 9:20) but it did not typically indwell them individually to set them apart. Among Yesuha's followers God's Spirit continued to instruct (First Corinthians 2:13) and act (Romans 15:19). It also became a witness (Acts 5:32, Hebrews 10:15, First John 3:24) and seal (Ephesians 1:13, 4:30) of their new relationship with God, but through the gifts (First Corinthians 12, Hebrews 2:4) and virtues (Galatians 5:22-23) it imparts, not its miracles (Matthew 7:22-23).
Meaning for Yeshua's followers in Modern Times
We should all know as much about our vocation as God is willing to reveal. Sometimes all we are told is, "Be patient."
We should pray about when God desires us to use isolation to be set apart for him, or to use dedication to set apart items for him. Remember that people were healed by touching Yeshua's tallit (Mark 5:30) or by touching handkerchiefs sent by Paul (Acts 19:12).
We should intercede in prayer.
The Apostolic Writings contain accounts of God's Spirit being transmitted to new believers by the laying on of hands. We should be aware of those of Yeshua's followers who do not have God's Spirit dwelling within them and pray for them.
We should pray for Spiritual gifts (Luke 11:13, First Corinthians 12:31) since these are the witness and seal of our new covenant relationship with God (Hebrews 10:15-17).