9 In order to understand more deeply this reflection on the two types of substance— hypostasis and hyparchonta —and on the two approaches to life expressed by these terms, we must continue with a brief consideration of two words pertinent to the discussion which can be found in the tenth chapter of the Letter to the Hebrews . I refer to the words hypomone (10:36) and hypostole (10:39). Hypo- mone is normally translated as “patience”—perseverance, constancy. Knowing how to wait, while patiently enduring trials, is necessary for the believer to be able to “receive what is promised” (10:36). In the religious context of ancient Judaism, this word was used expressly for the expectation of God which was characteristic of Israel, for their persevering faithfulness to God on the basis of the certainty of the Covenant in a world which contradicts God. Thus the word indicates a lived hope, a life based on the certainty of hope. In the New Testament this expectation of God, this standing with God, takes on a new significance: in Christ, God has revealed himself. He has already communicated to us the “substance” of things to come, and thus the expectation of God acquires a new certainty. It is the expectation of things to come from the perspective of a present that is already given. It is a looking-forward in Christ's presence, with Christ who is present, to the perfecting of his Body, to his definitive coming. The word hypostole , on the other hand, means shrinking back through lack of courage to speak openly and frankly a truth that may be dangerous. Hiding through a spirit of fear leads to “destruction” ( Heb 10:39). “God did not give us a spirit of timidity but a spirit of power and love and self-control”—that, by contrast, is the beautiful way in which the Second Letter to Timothy (1:7) describes the fundamental attitude of the Christian.
Source: Spe Salvi (Vatican.va)