Psalms 3:6

I will not be afraid - As the result of this new proof of the divine protection, and in view of all that God has done and has promised, the psalmist now says that he would not be afraid though any number of foes should rise up against him. Perhaps this confiding and exulting spirit may be regarded in some measure as the “result” of the calm and refreshing slumber which he had enjoyed. The mind as well as the body had been refreshed and invigorated. With the bright light of a new morning he looked with more cheerful views and hopes on the things around him, and felt new strength to meet the dangers to which he was exposed. Who in trouble and sorrow has not felt this? Who has not experienced the influence of the slumbers of a night and of the light of the morning, in giving new vigour and inspiring new hopes, as if the returning day was an emblem of brighter scenes in life, and the passing away of the shades of night a token that all trouble and sorrow would flee away?

Of ten thousands of people - Myriads: Though myriads are arrayed against me. He does not, of course, pretend to any exactness here; but he felt that the number of his enemies was very great. This “was” the case in the rebellion of Absalom. Ahithophel proposed to Absalom to “choose out twelve thousand men” with whom he might pursue after David, implying that the number with him was actually much greater than that, 2 Samuel 17:1)

That have set themselves against me - That have arrayed themselves against me; or that have risen up in rebellion against me.

Round about - Intending to hem me in on every side. Of course this was to be apprehended in such a rebellion; yet David says that he could now look with calmness on all this, for he had confidence in God. Compare Psalms 56:3.