Unbelief leaves our dearest interests and concerns in our own hands. It commits nothing to God. Consequently, it fills the heart with distracting fears when imminent danger threatens us. If this is your case, you will be surrounded with terror whenever you are surrounded with danger and trouble. Believers have this advantage: they have committed by faith all that is precious and valuable to them in God’s hands. They have committed the keeping of their souls (1 Peter 4:19) and all their eternal concerns (2 Tim. 1:14) to Him. Because these things are in safe hands, they are not distracted with fears about matters of less value. They entrust these to God and enjoy the peace and quietness of a resigned soul (Prov. 163). But as for you, you keep your life, liberty, and soul (which is infinitely greater than these other things) in your own hands in the day of trouble. You do not know what to do with them or how to dispose of them.
Oh, these are the dreadful frights in which unbelief leaves people! It is a foundation of fears and distractions. Indeed, it cannot but distract and bewilder carnal people, in whom it reigns in full strength. Sad experience shows us what fear (the remains and relics of unbelief) produces in the best people.w ho are not fully free from it. If the relics of unbelief can darken and cloud their evidences, if it can draw such sad and frightful conclusions in their hearts (despite all the contrary experience of their lives), what unrelieved terrors must it produce in those who are under its full strength and dominion!
John Flavel, Triumphing Over Sinful Fear, 38-39