(Rm 4, 18) He believed, hoping against hope[18] He believed, hoping against hope, that he would become "the father of many nations," according to what was said, "Thus shall your descendants be."(CCC 706) Against all human hope, God promises descendants to Abraham, as the fruit of faith and of the power of the Holy Spirit (Cf. Gen 18:1-15; Lk 1:26-38. 54-55; Jn 1:12-13; Rom 4:16-21). In Abraham's progeny all the nations of the earth will be blessed. This progeny will be Christ himself (Cf. Gen 12:3; Gal 3:16), in whom the outpouring of the Holy Spirit will "gather into one the children of God who are scattered abroad" (Cf. In 11:52). God commits himself by his own solemn oath to giving his beloved Son and "the promised Holy Spirit... [who is] the guarantee of our inheritance until we acquire possession of it" (Eph 1:13-14; cf. Gen 22:17-19; Lk 1:73; Jn 3:16; Rom 8:32; Gal 3:14). (CCC 165) It is then we must turn to the witnesses of faith: to Abraham, who "in hope... believed against hope" (Rom 4:18); to the Virgin Mary, who, in "her pilgrimage of faith", walked into the "night of faith" (LG 58; John Paul II, RMat 18) in sharing the darkness of her son's suffering and death; and to so many others: "Therefore, since we are surrounded by so great a cloud of witnesses, let us also lay aside every weight, and sin which clings so closely, and let us run with perseverance the race that is set before us, looking to Jesus the pioneer and perfecter of our faith" (Heb 12:1-2). (CCC 1819) Christian hope takes up and fulfills the hope of the chosen people which has its origin and model in the hope of Abraham, who was blessed abundantly by the promises of God fulfilled in Isaac, and who was purified by the test of the sacrifice (Cf. Gen 17:4-8; 22:1-18). "Hoping against hope, he believed, and thus became the father of many nations" (Rom 4:18).