Nun. [These letters (Nun, etc.) are one of the miracles of the Quran, and none but Allah (Alone) knows their meanings]. By the pen and what the (angels) write (in the Records of men).
So (O Muhammad SAW) obey not the deniers [(of Islamic Monotheism those who belie the Verses of Allah), the Oneness of Allah, and the Messenger of Allah (Muhammad SAW), etc.]
We hope that our Lord will give us in exchange a better (garden) than this. Truly, we turn to our Lord (wishing for good that He may forgive our sins, and reward us in the Hereafter)."
(Remember) the Day when the Shin shall be laid bare (i.e. the Day of Resurrection) and they shall be called to prostrate (to Allah), but they (hypocrites) shall not be able to do so,
Their eyes will be cast down, ignominy will cover them; they used to be called to prostrate (offer prayers), while they were healthy and good (in the life of the world, but they did not).
So wait with patience for the Decision of your Lord, and be not like the Companion of the Fish, when he cried out (to Us) while he was in deep sorrow. (See the Quran, Verse 21:87).
Had not a Grace from his Lord reached him, he would indeed have been (left in the stomach of the fish, but We forgave him), so he was cast off on the naked shore, while he was to be blamed.
And verily, those who disbelieve would almost make you slip with their eyes through hatredness when they hear the Reminder (the Quran), and they say: "Verily, he (Muhammad SAW) is a madman!"
IMPORTANT: All Scripture text has context and background. Scripture should never be read literally or in isolation. Always seek clarification from religious scholars and teachers. In general, Scripture adheres to four principles: (1) Literal Meaning - What the Scripture says (2) Historical Setting - The story events; how the Scripture was understood in its time (3) Grammar - The surrounding sentence and paragraph; textual context (4) Synthesis - A comparison with similar Scripture to give a better contextual understanding