The monotheist is like a servant to a single master. The polytheist is like a servant to many masters who argue and fight over him — pulled in every direction, with no peace.
"They rejoiced at what knowledge they already possessed." — An indispensable lesson for all of humankind, repeated throughout the Sūrah (verses 4–5, 35, 56, 69).
Every deed is sealed with praise. Allah the Creator began with praise — "Praise be to Allah, who created the heavens and the earth" — and ended with praise — "Praise be to Allah, Lord of the worlds."

The Quran leaves nothing concerning the affairs of this life and the Hereafter except that it clarifies it — either summarily or in detail — and sets parables for it.