Surah Al-Hijr (The Rock): Chapter 15 (line 90-99)

90. Just as We sent down to the separatists.

91. Those who made the Quran obsolete.

92. By your Lord, we will question them all.

93. About what they used to do.

94. So proclaim openly what you are commanded, and turn away from the polytheists.

95. We are enough for you against the mockers.

96. Those who set up another god with God. They will come to know.

97. We are aware that your heart is strained by what they say.

98. So glorify the praise of your Lord, and be among those who bow down.

99. And worship your Lord in order to attain certainty.

My Interpretation: 

The major takeaway from this is the idea that Muhammad is being prepared for a battle of the mind, he has never encountered yet. There were those given the Quran revelations before Muhammad, in another nation, but the messages were twisted and manipulated to be written with a subjective intention instead of taken for their natural source of information.

Muhammad will be going up against the Pagans who have worshipped hundreds of different gods for thousands of years. He is told to not fear this task and to know that the Angels and Allah are behind him as he puts forth effort to spread the messages.

Gabriel is telling Muhammad that the Angels of Allah understand how Muhammad is under a lot of stress to overtake such a duty or burden on his shoulders and try to change the Arab world, but he is on the right path and has Divine support.

Do you notice that as seekers of God? Do you notice that when you set out to help spread the messages, with TRUE intention to not hurt, judge, or create division, you are somehow supported to do so? Notice that next time you set your heart on a spiritual mission and duty.