Fire And Spirit

Dic mihi, quanta continet ignis in se? iv, id est, urit, illuminat, calelfacit et sanctificat. Sanctificare autem proprie in sua natura non habet, licet figurant Spiritus sancti teneat, qui urit vitia, calefacit frigidam animam, sanctificat peccatorem, illuminat cor, unde tenebras ignorantiae fugat. Sanctus Isidorus Hispalensis, De Veteri et Novo Testamento Quaestiones, Quaestio XXVII Source: Migne PL 83.204b-c

Tell me, what does fire contain in itself? Four things, that is, it burns, it illuminates, it warms and it sanctifies. That it sanctifies it does not have in its own nature, but does so as a figure of the Holy Spirit, who is the One who burns out vices, warms the cold soul, sanctifies the sinner, illuminates the heart, from whence the darkness of ignorance flies. Saint Isidore of Seville, Questions on the Old and New Testaments, Question 27