Bede : David therefore said to him: Whose are you, or from where? etc. It is a rule of the Church to inquire of those who defect to her from heretics through their teachers; who, before they fled, what they thought about faith, to where they tend in the future in mind. And when they have known them to contradict heresies with full intensity, and to favor the Catholic faith, then and only then should they apply the sacraments of the same faith to be reconciled with them, lest they seem to throw holy things to the dogs, and pearls to the swine. Of whose, he said, are you listeners, and of what, or to which sect are you proposing now to belong? It is necessary to reply, he who seeks to escape the snares of the heretics: I confess, I have been darkened by sins, having been devoted to listening to the heretics; but my master, who imbued me with errors, has left me: because where wars were waged against the Church, he found me less suitable in tongue or intellect for this contest; nor did he wish to take me any further into such a conflict with him. Truly, we breaking out from the south, that is, light, promising our perfect and Spirit-breathing doctrine, and brought not a few of the gentiles to our sect, and in no small part obstructed the faith of the Church. — Commentary on Samuel