Jamieson, Fausset and Brown on 2 Kings 6:17

17. Elisha prayed, and said, Lord, I pray thee, open his eyes, that he may see--The invisible guard of angels that encompass and defend us (Psa 34:7). The opening of the eyes, which Elisha prayed for, were those of the Spirit, not of the body--the eye of faith sees the reality of the divine presence and protection where all is vacancy or darkness to the ordinary eye. The horses and chariots were symbols of the divine power (see on 2Ki 2:12); and their fiery nature denoted their supernatural origin; for fire, the most ethereal of earthly elements, is the most appropriate symbol of the Godhead [Keil].

2Ki 6:18-23. His Army Smitten with Blindness.