To whom would the Apostles be sent? In the Gospel Jesus seemed to limit his mission to Israel alone: "I was sent only to the lost sheep of Israel" (Mt 15: 24). In a similar way he seemed to restrict the mission entrusted to the Twelve: "These Twelve Jesus sent out, charging them: "Go nowhere among the Gentiles, and enter no town of the Samaritans, but go rather to the lost sheep of the house of Israel'" (Mt 10: 5ff.).
A certain rationally inspired modern criticism saw these words as showing a lack of universal awareness by the Nazarene. Actually, they should be understood in the light of his special relationship with Israel, the community of the Covenant, in continuity with the history of salvation.
According to the Messianic expectation, the divine promises directly addressed to Israel would reach fulfilment when God himself had gathered his people through his Chosen One as a shepherd gathers his flock: "I will save my flock, they shall no longer be a prey.... I will set up over them one shepherd, my servant David, and he shall feed them; he shall feed them and be their shepherd. And I, the Lord, shall be their God, and my servant David will be prince among them" (Ez 34: 22-24).
Jesus is the eschatological shepherd who gathers the lost sheep of the house of Israel and goes in search of them because he knows and loves them (cf. Lk 15: 4-7, Mt 18: 12-14; cf. also the figure of the Good Shepherd in Jn 10: 11ff.). Through this "gathering together", the Kingdom of God is proclaimed to all peoples: "I will set my glory among the nations; and all the nations shall see my judgment which I have executed, and my hand which I have laid on them" (Ez 39: 21). And Jesus followed precisely this prophetic indication. His first step was to "gather together" the people of Israel, so that all the people called to gather in communion with the Lord might see and believe.
Thus, the Twelve, taken on to share in the same mission as Jesus, cooperate with the Pastor of the last times, also seeking out the lost sheep of the house of Israel, that is, addressing the people of the promise whose reunion is the sign of salvation for all peoples, the beginning of the universalization of the Covenant.
Far from belying the universal openness of the Nazarene's Messianic action, the initial restriction to Israel of his mission and of the Twelve thus becomes an even more effective prophetic sign. After Christ's passion and Resurrection, this sign was to be made clear: the universal character of the Apostles' mission was to become explicit. Christ would send the Apostles "to the whole creation" (Mk 16: 15), to "all nations", (Mt 28: 19, Lk 24: 47), "to the ends of the earth" (Acts 1: 8).
And this mission continues. The Lord's command to gather the peoples together in the unity of his love still continues. This is our hope and also our mandate: to contribute to this universality, to this true unity in the riches of cultures, in communion with our true Lord Jesus Christ.
[Pope Benedict, General Audience 22 March 2006]