Holiness is analysed as a universal vocation of humankind and as a gift from God, springing from the Holy Trinity and shared through the grace of the Holy Spirit within the Church. Drawing upon Holy Scripture and the Holy Fathers — including Dumitru Stăniloae, Gregory of Nyssa, Maximus the Confessor and Nectarius of Aegina — the article demonstrates that holiness entails purification, virtue and spiritual experience, culminating in the deification of humankind and the sanctification of all creation.