When the servant of the man of God rose early in the morning and went out, behold, an army with horses and chariots was round about the city. And the servant said, “Alas, my master! What shall we do?” Then Elisha prayed, and said, “O LORD, I pray Thee, open his eyes that he may see.” So the LORD opened the eyes of the young man, and he saw; and behold, the mountain was full of horses and chariots of fire round about Elisha. – 2 Kings 6:15,17

Already the horses and chariots of fire were round about Elisha; but his servant could not see one of them, because they were spiritual chariots and spiritual horses-angelic beings belonging to the purely spiritual domain; and as yet the youth had not entered the spiritual region and had no eyes with which to see into it. When God had given him spiritual eyes, then there began to break upon his vision that strange sight-ethereal, aerial, nay, spiritual, but yet most real; that sight which revived his soul with the conviction that the prophet was safe, since the ministers of God, as flames of fire, flashed to and fro; and like an army, with horses and chariots, showed themselves strong for the defense of the servant of Jehovah. How surprised he was! How great his amazement! How content his mind! He and his master were mysteriously defended, beyond all fear of danger. O my hearers, as yet strangers to the things of God; if the Lord would open your eyes at once, you would be astonished indeed; for as yet you have no idea, you cannot have any idea, what the spiritual life is, nor what spiritual realities must be: neither can you have any true idea of them till you are quickened of the Lord. You may talk about spiritual subjects, and discuss them, and think yourselves theologians; but you resemble deaf persons criticizing music, and blind men describing pictures. You are not qualified even to express an opinion upon the matter till you are created anew in Christ Jesus and brought within range of the spiritual and the heavenly. “Except a man be born again, he cannot see the kingdom of God.” Let the prayer go up, then, from all enlightened hearts, for those who are not as yet walking in the light: “Lord, open the eyes of the young men, that they may see!” ~ C.H. Spurgeon

https://www.blueletterbible.org/comm/spurgeon_charles/sermons/2215.cfm