4. In the parable of the sower and the sowing, the growth of the Kingdom of God certainly appears as the fruit of the work of the sower, but it is in relation to the soil and the climatic conditions that the sowing produces a harvest: "where the hundred, where the sixty, where the thirty" (Mt 13:8). The soil means the inner readiness of men. Therefore, according to Jesus, the growth of the Kingdom of God is also conditioned by man. Human free will is responsible for this growth. This is why Jesus recommends to all to pray: "Thy kingdom come" (cf. Mt 6:10; Lk 11:2): it is one of the first questions of the Pater noster.

[John Paul II, General Audience 25 September 1991]