The focus of the early revelations

The revelations that descended upon Muhammad from about 610 onward spoke primarily of God the One, Who is both the Creator of the world and its Judge. He will call mankind before His judgment unless they follow the commands to love their neighbors, to do justice, and to act honestly. In the early, short suras, as the chapter of the Koran later came to be called, the terrors of the Day of Judgment are depicted in brief and powerful, rhyming sentences that follow each other like sharp lightning and roaring thunder. The Meccans did not find this message very convincing; in particular, the idea of the resurrection of the dead did not make much sense to them. But the revelations Muhammad repeatedly received to counter such doubts argued that even the earth, seemingly dead in winter, could bring forth fresh greenery in the spring, and that the miracle of conception and birth is not less than that of the resurrection of the flesh.

-Annemarie Schimmel, And Muhammad Is His Messenger: The Veneration of the Prophet in Islamic Piety (Chapel Hill: The University of North Carolina Press, 1985), p. 12.

[Re-reading for a course on Islam that I am TA'ing for this semester alhamdullilah. I thought she offered this description of the early revelations in a concise and lovely manner.]