CIC 706 Against all human hope, God promises descendants to Abraham, as the fruit of faith and of the power of the Holy Spirit.1 In Abraham’s progeny all the nations of the earth will be blessed. This progeny will be Christ himself,2 in whom the outpouring of the Holy Spirit will “gather into one the children of God who are scattered abroad.”3 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.”4

1 Cf. Gen 18:1-15; Lk 1:26-38. 54-55; Jn 1:12-13; Rom 4:16-21.
2 Cf. Gen 12:3; Gal 3:16.
3 Cf. In 11:52.
4 Eph 1:13-14; cf. Gen 22:17-19; Lk 1:73; Jn 3:16; Rom 8:32; Gal 3:14.