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 6:17

We ask the Lord to work a marvel. We would have you, dear friends, receive what no education can ever get you, what no graduation at any university can ever bestow upon you; we want you to obtain what no years of experience or of study can achieve; we want you to possess what no imitation of other people will gain for you; we want you to experience a change which only the Lord Himself can work in you. We would have you pass from nature’s darkness into God’s marvellous light, from an awful blindness into a clear vision of things otherwise invisible… “Lord, let them receive sight, through the gracious working of Thy Holy Spirit!” The reason for our prayer is because we ourselves have been made to see. Had this miracle of grace not taken place within us, we should have had no thought of prayer for you; but now our whole heart goes with the plea. Once we were as you are. Our eyes were blinded so that we saw neither our foes in all their terror, nor the glory of the Lord round about us. Like blind Samsons, we went through the weary drudgery of earth surrounded by our foes. At length a glimmering of the light fell upon us, like a lightning-flash, showing us our sin; and after we were thus illuminated, we endured a great fight of afflictions. Without were fightings, within were fears. Our enemies were round about us, and we knew not what to do. But some man of God prayed for us, and one day our eyes were turned toward the hills from whence cometh all aid to terror-stricken men. The Lord was there, though we knew Him not; but yet we looked to Him and were enlightened, and our faces were not ashamed; for round about Him the mountain was full of chariots and horses of fire. “For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ.” ~ C.H. Spurgeon

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