What, then, was the motive of Anglicans, in maintaining the unity of particular churches, and the institution of bishops cohering with it, to be necessary, while they denied the necessity of unity in the Church universal, or of a Primate's institution, to effect universal unity? What induced them to assert incompatibilities, and defend them as a matter of life and death? The evidence of the Scriptures, and the unquestionable belief of all Christian antiquity, extorted from them the acknowledgment that unity was a mark of the Church, and the ascription to Christ of the institution of bishops as necessary for the forming and maintaining unity. _But the fixed purpose of defending their schism, and their determination to reject the Primacy, urged them to deny that unity in the whole Church was ordered and provided for by Christ._ The result of these affirmatives and negatives was a doctrinal[59] monster of incomparable ugliness, an outrage on the light both of nature and of revelation, as incapable of defence, as abhorrent from reason and from grace. B. The second Protestant opinion has been set forth at length by[60] Vitringa, and supported with all his ingenuity. It is that of those who distinguish a two-fold unity of the Church, one interior, spiritual, proceeding from union with one and the same invisible Head, Jesus Christ, and completed and perfected by the inhabitation of the Holy Spirit, and the bestowal of heavenly gifts; the other exterior, visible, depending on profession of the same faith, participation of the same sacraments, obedience to the same superiors. Having made this distinction, they proceed to argue for the purpose of proving that while the former unity is universal, and absolutely necessary, the latter is neither universal nor necessary, save hypothetically, (of which hypothesis Vitringa nowhere explains the nature,) and so is capable both of extension and restriction. In a word, they attach simple and absolute necessity and universality to the spiritual and invisible unity, but by no means to the external and visible.