For I am the LORD, I do not change; therefore you are not consumed, O sons of Jacob. – Malachi 3:6

Beloved Christians, you who have been believers for years, if you begin to live by your frames and feelings, you will get into the same condition. “I do not feel like praying,” says one. Then is the time when you ought to pray most, for you are evidently most in need; but if you keep observing whether or not you are in the proper frame of mind for prayer, you will not pray. “I cannot grasp the promises,” says another; “I should like to joy in God, and firmly believe in His Word; but I do not see anything in myself that can minister to my comfort.” Suppose you do not. Are you, after all, going to build upon yourself? Are you trying to find your ground of consolation in your own heart? If so, you are on the wrong tack…I think it is a great lesson to learn in spiritual things, to believe in Christ, and His finished salvation, quite as much as when you are down as when you are up; for Christ is not more Christ on the top of the mountain than He is in the bottom of the valley, and He is no less Christ in the storm by midnight than He is in the sunshine by day. Do not begin to measure your safety by your comfort; but measure it by the eternal Word of God, which you have believed, and which you know to be true, and on which you rest…

If we have Christ with us, whether the days are light or dark, we walk in the light, and our soul is happy and glad; but apart from Christ, the estimate of life which is given here is an exactly accurate one-a little brightness and long darkness, a flash and then midnight. God save you from living a merely natural life! May you rise to the supernatural! May you get out of the lower life of the mere animal into the higher life of the regenerated soul! If the life of God be in you, then you shall go from strength to strength like the sun that shineth unto the perfect day. ~ C.H. Spurgeon

https://www.blueletterbible.org/comm/spurgeon_charles/sermons/2264.cfm