CCC 63 Israel is the priestly people of God, “called by the name of the LORD”, and “the first to hear the word of God”,1 the people of “elder brethren” in the faith of Abraham.

CCC 708 This divine pedagogy appears especially in the gift of the Law.2 God gave the Law as a “pedagogue” to lead his people toward Christ.3 But the Law’s powerlessness to save man deprived of the divine “likeness,” along with the growing awareness of sin that it imparts,4 enkindles a desire for the Holy Spirit. The lamentations of the Psalms bear witness to this.

CCC 709 The Law, the sign of God’s promise and covenant, ought to have governed the hearts and institutions of that people to whom Abraham’s faith gave birth. “If you will obey my voice and keep my covenant,. .. you shall be to me a kingdom of priests and a holy nation.”5 But after David, Israel gave in to the temptation of becoming a kingdom like other nations. The Kingdom, however, the object of the promise made to David,6 would be the work of the Holy Spirit; it would belong to the poor according to the Spirit.

CCC 751 The word “Church” (Latin ecclesia, from the Greek ek-ka-lein, to “call out of”) means a convocation or an assembly. It designates the assemblies of the people, usually for a religious purpose.7 Ekklesia is used frequently in the Greek Old Testament for the assembly of the Chosen People before God, above all for their assembly on Mount Sinai where Israel received the Law and was established by God as his holy people.8 By calling itself “Church,” the first community of Christian believers recognized itself as heir to that assembly. In the Church, God is “calling together” his people from all the ends of the earth. The equivalent Greek term Kyriake, from which the English word Church and the German Kirche are derived, means “what belongs to the Lord.”

CCC 762 The remote preparation for this gathering together of the People of God begins when he calls Abraham and promises that he will become the father of a great people.9 Its immediate preparation begins with Israel’s election as the People of God. By this election, Israel is to be the sign of the future gathering of All nations.10 But the prophets accuse Israel of breaking the covenant and behaving like a prostitute. They announce a new and eternal covenant. “Christ instituted this New Covenant.”11

CCC 1539 The chosen people was constituted by God as “a kingdom of priests and a holy nation.”12 But within the people of Israel, God chose one of the twelve tribes, that of Levi, and set it apart for liturgical service; God himself is its inheritance.13 A special rite consecrated the beginnings of the priesthood of the Old Covenant. The priests are “appointed to act on behalf of men in relation to God, to offer gifts and sacrifices for sins.”14

CCC 2060 The gift of the commandments and of the Law is part of the covenant God sealed with his own. In Exodus, the revelation of the “ten words” is granted between the proposal of the covenant15 and its conclusion – after the people had committed themselves to “do” all that the Lord had said, and to “obey” it.16 The Decalogue is never handed on without first recalling the covenant (“The LORD our God made a covenant with us in Horeb.”).17

CCC 2085 The one and true God first reveals his glory to Israel.18 The revelation of the vocation and truth of man is linked to the revelation of God. Man’s vocation is to make God manifest by acting in conformity with his creation “in the image and likeness of God”:
There will never be another God, Trypho, and there has been no other since the world began. .. than he who made and ordered the universe. We do not think that our God is different from yours. He is the same who brought your fathers out of Egypt “by his powerful hand and his outstretched arm.” We do not place our hope in some other god, for there is none, but in the same God as you do: the God of Abraham, Isaac and Jacob.19

CCC 2810 In the promise to Abraham and the oath that accompanied it,20 God commits himself but without disclosing his name. He begins to reveal it to Moses and makes it known clearly before the eyes of the whole people when he saves them from the Egyptians: “he has triumphed gloriously.”21 From the covenant of Sinai onwards, this people is “his own” and it is to be a “holy (or ”consecrated“: the same word is used for both in Hebrew) nation,”22 because the name of God dwells in it.

1 Deut 28: 10; Roman Missal, Good Friday, General Intercession VI; see also Ex 19:6.
2 Cf. Ex 19-20; Deut 1-11; 29-30.
3 Gal 3:24.
4 Cf. Rom 3:20.
5 Ex 19:5-6; Cf. 1 Pet 2:9.
6 Cf. 2 Sam 7; Ps 89; Lk 1:32-33.
7 Cf. Acts 19:39.
8 Cf. Ex 19.
9 Cf. Gen 12:2; 15:5-6.
10 Cf. Ex 19:5-6; Deut 7:6; Isa 2:2-5; Mic 4:1-4.
11 LG 9; cf. Hos 1; Isa 1:2-4; Jer 2; 31:31-34; Isa 55:3.
12 Ex 19:6; cf. Isa 61:6.
13 Cf. Num 1:48-53; Josh 13:33.
14 Heb 5:1; cf. Ex 29:1-30; Lev 8.
15 Cf. Ex 19.
16 Cf. Ex 24:7.
17 Deut 5:2.
18 Cf. Ex 19:16-25; 24:15-18.
19 St. Justin, Dial. cum Tryphone Judaeo 11, 1: PG 6, 497.
20 Cf. Heb 6:13.
21 Ex 15:1 cf. 3:14.
22 Cf. Ex 19:5-6.