The promise is given the Church founded on the person of Apostle Peter, not to any variety, especially the less faithful kind that only knows to protest against the Gospel.
Sorry, annalex. The body of Christ is the one true church and has little or nothing to do with Catholicism. Catholics who know Christ as saviour are included in the one true church, of course. We believers are all counted as the one true church. Has zilch to do with any denomination.