Saying that revelation is progressive is not the same as saying that one religion leads to another.
Progressive revelation is a core teaching in the
Bahá'í Faith that suggests that religious truth is revealed by God progressively and cyclically over time through a series of divine
Messengers, and that the teachings are tailored to suit the needs of the time and place of their appearance.
[1][2] Thus, the
Bahá'í teachings recognize the divine origin of several world religions as different stages in the history of
one religion, while believing that the revelation of
Bahá'u'lláh is the most recent (though not the last—that there will never be a last), and therefore the most relevant to modern society.
[1]https://en.wikipedia.org/wiki/Progressive_revelation_Baha'i
Islam was revealed for a certain culture at a certain time and place. I do not believe all Christians should have dropped their laws and beliefs about marriage and accepted God's new law and had multiple wives.
I do not necessarily believe that the Dispensation of Muhammad abrogated all the Dispensations that came before it because that is not in the Baha'i Writings. All that Shoghi Effendi said is this:
“In conclusion of this theme, I feel, it should be stated that the Revelation identified with Bahá’u’lláh abrogates unconditionally all the Dispensations gone before it.....” God Passes By, p. 100
If you click on the link above you can read the rest of that paragraph on page 100. In short, the Revelation of Baha'u'llah does not abrogate the religions of the past, only the Dispensations of the past, because God is working through Baha'u'llah in this new religious dispensation.
Dispensation
- the divine ordering of the affairs of the world.
- an appointment, arrangement, or favor, as by God.
- a divinely appointed order or age:
e.g. the old Mosaic, or Jewish, dispensation; the new gospel, or Christian, dispensation.
Definition of dispensation | Dictionary.com
Shoghi Effendi explains now it is
not the religions that were abrogated. No religion can ever be abrogated because all the revealed religions were the Truth from God.
“Let no one, however, mistake my purpose. The Revelation, of which Bahá’u’lláh is the source and center, abrogates none of the religions that have preceded it, nor does it attempt, in the slightest degree, to distort their features or to belittle their value. It disclaims any intention of dwarfing any of the Prophets of the past, or of whittling down the eternal verity of their teachings. It can, in no wise, conflict with the spirit that animates their claims, nor does it seek to undermine the basis of any man’s allegiance to their cause. Its declared, its primary purpose is to enable every adherent of these Faiths to obtain a fuller understanding of the religion with which he stands identified, and to acquire a clearer apprehension of its purpose. It is neither eclectic in the presentation of its truths, nor arrogant in the affirmation of its claims. Its teachings revolve around the fundamental principle that religious truth is not absolute but relative, that Divine Revelation is progressive, not final. Unequivocally and without the least reservation it proclaims all established religions to be divine in origin, identical in their aims, complementary in their functions, continuous in their purpose, indispensable in their value to mankind.” The World Order of Bahá’u’lláh, pp, 57-58
Fundamental Principle of Religious Truth