When the seraphim before God's throne cry “Holy, holy, holy” (Isa. 6.3; cf. Rev. 4.8), they are engaging in an ascriptive tautology. God is holy and by that fact defines holiness. “Hallowed be thy name” is a prayer that the intrinsic holiness of God be established and recognized within creation, that is, that God's kingdom come and God's will be done (Matt. 6.9–10 par.; see Lord's Prayer).
In The Idea of the Holy, Rudolph Otto argues that the experience of the holy is irreducible to other categories. What he calls “the numinous” is a mysterium tremendum et fascinans, an awe‐inspiring phenomenon that both repels and attracts. The voice from the burning bush tells Moses to take off his shoes, for he is standing on holy ground, and Moses hides his face (Exod. 3.5–6; cf. Josh. 5.15). In the Bible, the elementary religious experience takes on a personal and ethical tone. The “wholly other,” the incomparable “Holy One” (Isa. 40.25), is also the transcendent creator (Ps. 95.6). God's holy name is vindicated by his acts in history (Ps. 98.1; Ezek. 36.22–27; John 12.28; Rev. 15.3–4). If God inspires fear, it is on account of his power and purity; if God attracts, it is by his creating love and redeeming grace. More precisely, God's power shows itself as love for the creature; God's purity shows itself as grace to transform the sinner. In his vision of “the King,” Isaiah finds his lips touched with a burning coal and his guilt is taken away (Isa. 6.5–7). The prophet is then set in God's service.
God's active claim upon a creature consecrates it. That is preeminently true of God's elect people. Yahweh is, especially in the book of Isaiah, “the Holy One of Israel.” He is “God and no mortal, the Holy One in [their] midst” (Hos. 11.9). Out of love, he has chosen this people for his own (Deut. 7.6–8). Belonging to the God who dwells among them, they are a holy nation (Exod. 19.5–6; Deut. 26.19; 28.9; Jer. 2.3). The divine gift brings an obligation: “You shall be holy for I am holy” (Lev. 11.44; 19.2; 20.7, 26).
According to the New Testament, Jesus is “the Holy One of God” (John 6.69; cf. Mark 1.24 par.; Luke 1.35; Acts 3.14), and through him God's favor has been extended to believing gentiles (1 Pet. 2.9; cf. Rom. 15.16). The church's vocation is to holiness (Eph. 1.3–4; 5.25–27; 1 Thess. 3.13). This again entails a way of life that distinguishes its members from the world (2 Cor. 6.16–7.1; 1 Thess. 4.3–7).
The way of holiness follows God by imitation (Eph. 4.24) and even participation (Heb. 12.10). Believers are “called [to be] saints” (Rom. 1.7; 1 Cor. 1.2; Col. 3.12). Having been sanctified in baptism (1 Cor. 6.11), Christians are to yield themselves to the righteousness of God for their sanctification to continue (Rom. 6.19–22). Their sanctification is the work within them of the Holy Spirit who has been given to them (Rom. 5.5; 1 Thess. 4.8). The promise is that of being made “partakers of the divine nature” (2 Pet. 1.3–11).
From the Exodus on, the ark of the covenant was a sign—and a dangerous one (1 Sam. 6.19; 2 Sam. 6.6–10)—of Yahweh's presence with Israel. In the Jerusalem Temple, it belonged in the “holy of holies” (1 Kings 8.6). Divinely significant objects, places, times, and people were “holy,” and the adjective became practically formulaic in the priestly documents of the postexilic period: God's holy house or Temple stood on God's holy mountain; it was served by a holy priesthood, and the feasts were holy days. A matching ethic was a prophetic concern (e.g., Mal. 3.4–5). In the New Testament, cultic terminology is turned toward conduct: “Present your bodies as a living sacrifice, holy and acceptable to God” (Rom. 12.1; cf. 1 Cor. 6.19–20; Eph. 2.21–22).