While we look not to the things that are seen but to the things that are unseen; for the things that are seen are temporal, but the things that are unseen are eternal. – 2 Corinthians 4:18

That there are devils, I think no Christian man will ever doubt; for at certain seasons we have been sadly conscious of a singularly terrible presence, with which our souls have been in agonizing conflict. In that tearful battle it has gone hard with us; our armor has been battered, our comfort has been grievously wounded, and our courage badly mauled. We have been saved as by the skin of our teeth. We hardly knew how to hold on at all, we were so sore beset by unnatural temptations, and suggestions nothing less than infernal. Then, at the Lord’s rebuke, this great adversary has taken sudden flight, and angels have come, and ministered to us new joys, and fruits of consolation, fresh from the tree of life. Then have we enjoyed communion with unseen messengers of God, who have seemed to bind up our wounds, and bring us on our way, and whisper peace. Did not an angel come to strengthen our Lord in Gethsemane? Have we not, in our measure enjoyed a similar visitation? It is a grand thing to see the hosts of God attending us, and to know that bright convoys of these shining ones will come to salute us at the last. It is a great gain to have the eyes opened, to see the Lord’s goodness and mercy following us all the days of our life, and ourselves, even here, dwelling in the house of the Lord for evermore. Open your eyes to spiritual things, and at once you are encouraged. The present is grievous, while you know only the visible; but the wilderness blossoms as the rose when you see the invisible. Project yourself beyond this narrow region, and behold the infinite, and sources of joy spring up around you everywhere. Poverty is forgotten in the midst of such riches; and even pain and disease have lost their sting. ~ C.H. Spurgeon

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