"The time is fulfilled and the Kingdom of God is at hand" (Mk 1,15). With these words Jesus of Nazareth begins his messianic preaching. In Jesus the Kingdom of God enters into the life and history of mankind, and it constitutes the fulfillment of the promises of salvation which Israel had received from the Lord.

Jesus is revealed as the Messiah, not because he aims at a temporal and political dominion according to the mentality of his contemporaries, but because in his mission, which culminates in his passion, death and resurrection, "all the promises of God find their Yes in him" (2 Cor 1,20).

In order to understand fully Jesus' mission, one must recall the Old Testament message which proclaims the saving kingship of the Lord. The Lord is acclaimed "king" because he freed his people in a marvelous way and led them with power and love to communion with him and with their brethren in the joy of freedom.

This faith in the saving kingship of the Lord prevented the monarchy from developing autonomously in the people of the Covenant as was the case in the other nations. The king is the chosen one, the Lord's anointed, and as such, he is the instrument by which God himself exercises his sovereignty.

After the exile, even though the institution of the monarchy ceases in Israel, there is a continuous growth of faith in the kingship which God exercises over his people and which will extend even to "the ends of the earth"(cf. Ps 95; 98).

Jesus refers to this hope of the Old Testament and proclaims its fulfillment. The Kingdom of God is the central theme of his preaching as is shown particularly in the parables (Mt 13,3-8; Mk 4,26-29; Mt 13,24-30; Mt 13,44-46).

The Kingdom of God, in its full and complete fulfillment, is certainly of the future; "until the Kingdom of God comes" (cf. Mk 9,1; Lk 22,18) the Lord's Prayer teaches us to pray for its coming, "thy Kingdom come" (Mt 6,10).

At the same time, however, Jesus states that the Kingdom of God "has already come" (Mt 12,28), "it is in the midst of you" (Lk 17,21) by means of the preaching and works of Jesus.

Moreover, from the whole of the New Testament it is evident that the Church, founded by Jesus, is the place where God's kingship is made present, in Christ, as the gift of salvation in faith, of new life in the Spirit, of communion in charity.

The conditions indicated by Jesus for entrance into the Kingdom can be summed up in the word "conversion." Through conversion the human person opens up to the gift of God (cf. Lk 12,32), who "calls you into his own kingdom and glory" (1 Thess 2,12); he welcomes the Kingdom as a child (Mk 10,15) and is prepared for whatever is required (cf, Lk 18,29; Mt 19,29; Mk 10,29).

The Kingdom of God demands a profound or new "justice" (Mt 5,20); it requires commitment in doing "God's will" (Mt 7,21); it calls for the interior simplicity "of children" (Mt 18,3; Mk 10,15); it implies the overcoming of the obstacle constituted by riches (cf. Mk 10,23-24).

The Beatitudes proclaimed by Jesus (cf. Mt 5,3-12) could be called the "Magna Carta" of the Kingdom of heaven They not only indicate the requirements of the Kingdom, they manifest first of all the work that God accomplishes in us by making us similar to his Son (Rom 8,29) and capable of having his sentiments (Phil 2,5 ff) of love and pardon (cf. Jn 13,34-35; Col 3,13).