The following is from a work-in-progress called The Qur'an: a Book Report, in which I read each surah of the Qur'an and write about what I learn.
Meccan surahs like this one come from the early period of the prophet's ministry, when he was a leader of a persecuted religious minority in Mecca who increasingly found themselves at odds with the powerful ruling tribe of that city, the Quraysh--who benefitted financially from an exploitive religio-economic system. Muhammad's message was threatening to the Quraysh, not so much because of its theology, but because of its radical call for social and economic justice. Ultimately, conflict with the Quraysh led to the famous exodus (or Hijra) of Muhammad and his fledgling community of faith from Mecca to Yathrib (later called Medina).
This Meccan surah seeks to comfort the prophet and his struggling community by reminding them of previous tyrannical rulers whom God overthrew, including the great Pharoah of Egypt, whose land God devastated before Moses led the Israelites on their Exodus. The implied message is: Take heart...God will ultimately bring justice.
In addition to comforting the prophet and his community, this surah gives a scathing indictment of social injustice, probably referring to the Quraysh tribe: "You (people) do not honor orphans, you do not urge one another to feed the poor, you consume inheritance greedily, and you love wealth with a passion." The surah concludes with a comforting promise of reward for the faithful Muslims: "You, soul at peace: return to your Lord well-pleased and well-pleasing; go in among My servants and into My garden."