Thou shalt not be afraid— The younger ones were to rest secure in the divine promise for protection. Amid the daily spectacles of mortality to which they were soon to be accustomed, it is added, Psalms 91:8. Only with thine eyes shalt thou behold, &c. i.e. "Thou shalt only have the discomfort of seeing those who may be dear to thee fall by their own guilt, and the just sentence passed upon them for their wicked murmurings and disobedience."
Related Commentaries of Psalms 91:5
Psalms 91:5-8
5 Thou shalt not be afraid for the terror by night; nor for the arrow that flieth by day;
6 Nor for the pestilence that walketh in darkness; nor for the destruction that wasteth at noonday.
7 A thousand shall fall at thy side, and ten thousand at thy right hand; but it shall not come nigh thee.
8 Only with thine eyes shalt thou behold and see the reward of the wicked.