Moralia in Job 580

Verse 21: 'The sound of terror is always in his ears; and when there is peace, he suspects ambushes.' 44. Simplicity of heart is a most fortified citadel. — For nothing is happier than a simple heart, because in that it shows innocence toward others, there is nothing which it dreads to suffer from others. For it has, as it were, a certain citadel of fortitude in its own simplicity. Nor is it apprehensive of suffering what it does not remember having done. Whence well is it said through Solomon: 'In the fear of the Lord is the confidence of strength' (Prov. 14:26). Who again says: 'A secure mind is like a continual feast' (Prov. 15:15). For the very tranquillity of security is as it were a continuation of refreshment.

But on the contrary the depraved mind is always in labours, because either it contrives evils to inflict, or it fears lest these be inflicted upon it by others. And whatever it devises against its neighbours, this it dreads to be devised against itself by its neighbours. It becomes suspicious on every side, trembling on every side. Everyone who comes to its memory is believed to seek adverse things. To him therefore who lacks the tranquillity of security, to him without doubt the sound of terror is always in his ears. And it often happens that any neighbour of his speaks to him simply, thinking nothing adverse. But when there is peace, he suspects ambushes, because he who always acts deceitfully does not reckon that anyone acts simply toward him. And because it is written:

'The impious man, when he has come into the depth of sins, despises' (Prov. 18:3), being wrapped in the darkness of his own iniquity, he now despairs of the light. Whence also there follows: