(Lo! those who disbelieve the revelations of Allah) in Muhammad and the Qur'an, (and slay the Prophets) i.e. ally themselves with those who slay the prophets (wrongfully) without them having committed any crime, (and slay those of mankind) who believed in the prophets (who enjoin equity) Allah's divine Oneness: (promise them a painful doom) which will spread out to their hearts.