While, in my view, there is a transcendent unity of faiths, there is also considerable difference and variety. (religion-online.org)
The Inquisition became a powerful instrument to ensure unity of faith, now that Christianity was triumphant, and also unity between Aragon and Castile, for it was the only institution that operated in both kingdoms. (faith.org.uk)
To be sure, ecclesial communion presupposes unity of faith in obedience to the one Lord. (firstthings.com)