CIC 543 Everyone is called to enter the kingdom. First announced to the children of Israel, this messianic kingdom is intended to accept men of all nations.1 To enter it, one must first accept Jesus’ word:
The word of the Lord is compared to a seed which is sown in a field; those who hear it with faith and are numbered among the little flock of Christ have truly received the kingdom. Then, by its own power, the seed sprouts and grows until the harvest.2

CIC 764 “This Kingdom shines out before men in the word, in the works and in the presence of Christ.”3 To welcome Jesus’ word is to welcome “the Kingdom itself.”3 The seed and beginning of the Kingdom are the “little flock” of those whom Jesus came to gather around him, the flock whose shepherd he is.5 They form Jesus’ true family.6 To those whom he thus gathered around him, he taught a new “way of acting” and a prayer of their own.7

CIC 2849 Such a battle and such a victory become possible only through prayer. It is by his prayer that Jesus vanquishes the tempter, both at the outset of his public mission and in the ultimate struggle of his agony.8 In this petition to our heavenly Father, Christ unites us to his battle and his agony. He urges us to vigilance of the heart in communion with his own. Vigilance is “custody of the heart,” and Jesus prayed for us to the Father: “Keep them in your name.”9 The Holy Spirit constantly seeks to awaken us to keep watch.10 Finally, this petition takes on all its dramatic meaning in relation to the last temptation of our earthly battle; it asks for final perseverance. “Lo, I am coming like a thief! Blessed is he who is awake.”11

1 Cf. Mt 8:11 10:5-7; 28:19.
2 LC 5; cf. Mk 4:14, 26-29; Lk 12:32.
3 LG 5.
4 LG 5.
5 Lk 12:32; cf. Mt 10:16; 26:31; Jn 10:1-21.
6 Cf. Mt 12:49.
7 Cf. Mt 5-6.
8 Cf. Mt 4:1-11; 26:36-44.
9 Jn 17:11; Cf. Mk 13:9, 23, 33-37; 14:38; Lk 12:35-40.
10 Cf. 1 Cor 16:13; Col 4:2; 1 Thess 5:6; 1 Pet 5:8.
11 Rev 16:15.