Newman on Interreligious Issues

It may be objected, that, if the feeling of a good conscience be evidence to us of our justification, then are persons in a justified state who are external to the Church, provided they have this feeling. I reply briefly,--for to say much here would be out of place,--that everyone will be judged according to his light and his privileges; and any man who has really the testimony of a good conscience is acting up to his light, whatever that is. . . It but shows that he is accepted in that state in which he is, be it one of greater favour or less, heathenism, schism, superstision, or heresy; and that, because his faults and errors at present are not wilful.

John Henry Newman, Plain and Parochial Sermons Volume V, "Sermon 17: The Testimony of Conscience."

But when he really gives himself up to God, when he gets himself honestly to say, "I sacrifice to Thee this cherished wish, this lust, this weakness, this scheme, this opinion: make me what Thou wouldest have me; I bargain for nothing; I make no terms; I seek for no previous information whither Thou are taking me; I will be what Thou wilt make me, and all that Thou wilt make me.

John Henry Newman, Plain and Parochial Sermons, Volume V, "Sermon 17: The Testimony of Conscience."