Though an host - Though an “army;” that is, any army, or any number of men in battle array. The past interposition of God in similar times of trouble and danger was to him a sufficient security that he had nothing to fear.
Should encamp against me - In battle array, or prepared for battle.
My heart shall not fear - He would not tremble; he would not feel that there was anything of which to be afraid. God had shown Himself superior to the power of hostile armies, and the psalmist felt assured that he might confide in Him.
Though war should rise against me - Though it should be proclaimed, and though all preparation should be made for it, I will not be afraid.
In this will I be confident - In such a case, in such an extremity or emergency, I would calmly trust in God. He would apprehend no danger, for he had seen that the Lord could deliver him.