Complex sentence: No single message, and therefore no single religion can be, according to Bahá'í belief, considered essentially superior to another, though a more recent message may be considered more relevant to humanity's current spiritual, social, and developmental context.
Split into simpler sentences: No single message, and therefore no single religion, can be (according to Bahá'í belief) considered essentially superior to another. Furthermore, a more recent message may be considered more relevant to humanity's current spiritual, social, and developmental context.