Religious truth is relative

The fundamental principle enunciated by Bahá'u'lláh ... is that religious truth is not absolute but relative, that Divine Revelation is a continuous and progressive process, that all the great religions of the world are divine in origin, that their basic principles are in complete harmony, that their aims and purposes are one and the same, that their teachings are but facets of one truth, that their functions are complementary, that they differ only in the nonessential aspects of their doctrines, and that their missions represent successive stages in the spiritual evolution of human society....

The Bahá'í Faith upholds the unity of God, recognizes the unity of His Prophets, and inculcates the principle of the oneness and wholeness of the entire human race. It proclaims the necessity and the inevitability of the unification of mankind, asserts that it is gradually approaching, and claims that nothing short of the transmuting spirit of God, working through His chosen Mouthpiece in this day, can ultimately succeed in bringing it about. It, moreover, enjoins upon its followers the primary duty of an unfettered search after truth, condemns all manner of prejudice and superstition, declares the purpose of religion to be the promotion of amity and concord, proclaims its essential harmony with science, and recognizes it as the foremost agency for the pacification and the orderly progress of human society....

Shoghi Effendi, The Promised Day is Come, Preface.