CCC 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

CCC 546 Jesus’ invitation to enter his kingdom comes in the form of parables, a characteristic feature of his teaching.3 Through his parables he invites people to the feast of the kingdom, but he also asks for a radical choice: to gain the kingdom, one must give everything.4 Words are not enough, deeds are required.5 The parables are like mirrors for man: will he be hard soil or good earth for the word?6 What use has he made of the talents he has received?7 Jesus and the presence of the kingdom in this world are secretly at the heart of the parables. One must enter the kingdom, that is, become a disciple of Christ, in order to “know the secrets of the kingdom of heaven”.8 For those who stay “outside”, everything remains enigmatic.9

1 Cf. Mt 8:11 10:5-7; 28:19.
2 LC 5; cf. Mk 4:14, 26-29; Lk 12:32.
3 Cf. Mk 4:33-34.
4 Cf. Mt 13:44-45; 22:1-14.
5 Cf. Mt 21:28-32.
6 Cf. Mt 13:3-9.
7 Cf. Mt 25:14-30.
8 Mt 13:11.
9 Mk 4:11; cf. Mt 13:10-15.