Basil of Caesarea's letter 207, to the clergy of Neocaesarea, tackles a quarrel between the parties. Although the underlying differences are doctrinal, the immediate points of contention are the singing of psalms and Cappadocian monasticism. A strong theme of heavenly citizenship runs through the letter and is traced from Basil's first mention of the monastics to the quotation from the hymn of Isaiah 26 with which he opens the description of a service at which psalms are sung. Though undoubtedly functioning here as a rhetorical device contrasting orderly monastic life with the disorganised attacks of his opponents, this theme lies at the heart of Basil's view of monasticism. He sees his monastics as citizens of heaven in the sense of living the ideal Christian life in which worship is central. Thus the theme of heavenly citizenship fits with ideas that associate human worship with that of angels. This concept has its full development in the hymn of Oxyrhynchus Papyrus 1786, Gregory of Nyssa's exposition of Psalm 150 as the eschatological union of human and angelic worship, and the poetry of Gregory Nazianzen in which that eschatological future breaks into the present.