There are two basic types of fear: servile and filial. Servile fear is the slave’s fear of a master who will punish him for wrongdoing. Filial fear, also known as reverential fear, is the good child’s fear of dishonoring a loving parent. The Spirit’s gift to us is filial fear, as befits adopted “sons in the Son.”
At this point one would do well to recall the traditional Catholic understanding of punishment. The one who does wrong to another has wilfully violated or withheld the good owed to that other, and therefore deserves to be deprived, against his will, of some good of his own. Punishment goes against what one would want for oneself according to sensuality or the will of nature; accordingly, it is displeasing. Rightly so: he who chooses to cling to a good in a disordered way, deserves to have some good taken away from him without his choice, for the restoration of order. Hence, one could say that servile fear is fear of being displeased, of being punished by a judge, and is thus essentially selfish; whereas filial fear is fear of being displeasing, of doing wrong to a friend, and is thus essentially concerned with the beloved, the honor and love due to him.
In this way, the more we love God, the less we will fear in the manner of slaves cowering before a punitive Master, but the more intensely we will hold in reverential fear His great paternal goodness, which is worthy of all of our loving service—indeed, worthy of far more than we can render to Him even in the measureless span of eternity—and against which we rightly fear to sin.
For Saint Thomas (and the larger tradition he inherits), there are two vices opposed to hope: despair and presumption (cf. II-II, qq. 20–21). Despair is a vice in the direction of defectiveness: it is to abandon one’s hope of attaining the goal of heaven when one is, in fact, capable of attaining it with God’s help. Presumption, on the contrary, is a vice in the direction of excess: one has an inflated hope, laying claim to some reward beyond one’s actual merits. Instead of soaring to heaven by God’s help (which is the very basis of our hope), we think to do it on our own—and that is a sin against hope.
Note that the one who despairs has a false understanding of God, much like a slave could have a false picture of a good master: God’s mercy is forgotten, and God’s desire to save us grows distant from our minds. One who presumes, on the other hand, has a false understanding of himself: he thinks he has what it takes to reach perfection. He loses the reverential fear that tells him how utterly poor he is as a creature and how great is the Lord’s uncreated glory. So he forgets God’s primacy in saving him.
WHAT PRECEPTS OR COMMANDS of the Law are given in regard to hope and fear (cf. II-II, qu. 22)? Saint Thomas observes that Sacred Scripture is constantly urging us to place our hope in God by way of promises, warnings, and commands, because so much is at stake when it comes to where we place, or do not place, our hope—no less a good than our very salvation, which can only come from God. God so loves us that He commands us to place our hope in Him, knowing what is best for us and willing our happiness.
Confronted with such fatherly generosity, how could we not love Him in return and run to Him with trust, casting off the slave’s despair and the presumption of the self-made man, approaching Him with reverent fear to receive from His outstretched hands the crown of immortality?