The text of his address follows, via Zenit, with my emphases:
In reading the Old Testament, one figure stands out among others: that of Moses, the man of prayer. Moses, the great prophet and leader during the time of the Exodus, carried out his role as mediator between God and Israel by becoming, among the people, the bearer of the divine words and commandments, by guiding them toward the freedom of the Promised Land, and by teaching the Israelites to live in obedience and trust toward God during their long sojourn in the desert; but also, and I would say especially, by praying. He prays for Pharaoh when God, through the plagues, was trying to convert the Egyptians' hearts (cf. Exodus 8:10); he asks the Lord to heal his sister Miriam who was struck with leprosy (cf. Numbers 12:9-13); he intercedes for the people who had rebelled, fearful of the scouts' report (cf. Numbers 14:1-19); he prays when fire was about to devour the camp (cf. Numbers 11:1-2) and when poisonous serpents were killing the people (cf. Numbers 21:4-9); he addresses himself to the Lord and reacts by protesting when the burden of his mission had grown too heavy (cf. Numbers 11:10-15); he sees God and speaks with him "face to face, as a man speaks to his friend" (cf. Exodus 24:9-17; 33:7-23; 34:1-10,28-35).
Also at Sinai, when the people ask Aaron to fashion for them a golden calf, Moses prays, thus carrying out in an emblematic way the true role of an intercessor. The episode is narrated in Chapter 32 of the Book of Exodus and has a parallel account in Deuteronomy Chapter 9. It is this episode that I would like to dwell upon in today's catechesis; and in particular on the prayer of Moses that we find in the Exodus account.
The people of Israel were at the foot of Mount Sinai while Moses, on the mountain, was awaiting the gift of the tablets of the Law, fasting for forty days and forty nights (cf. Exodus 24:18; Deuteronomy 9:9). The number forty has symbolic value and signifies the totality of experience, while fasting points to the fact that life comes from God, that it is he who sustains it. The act of eating, in fact, involves taking in the nourishment that sustains us; therefore fasting, or the renunciation of food, acquires in this case a religious significance: It is a way of indicating that man does not live by bread alone, but by every word that proceeds out of the mouth of the Lord (cf. Deuteronomy 8:3). Fasting, Moses shows himself to be awaiting the gift of the divine Law as a source of life: It reveals the Will of God and nourishes the heart of man, enabling him to enter into a covenant with the Most High, who is the fount of life, who is life itself.
But while the Lord, upon the mountain, gives the Law to Moses, at the foot of the mountain the people transgress it. Unable to withstand the mediator's delay and absence, the Israelites ask Aaron: "Make us a god, who shall go before us; as for this Moses, the man who brought us up out of the land of Egypt, we do not know what has become of him" (Exodus 32:1). Tired of a journey with an invisible God, now that Moses, the mediator, has also disappeared, the people ask for a tangible, touchable presence of the Lord, and find in the molten calf made by Aaron, a god made accessible, maneuverable, within man's reach. It is a constant temptation on the journey of faith: to elude the divine mystery by constructing a comprehensible god, corresponding to one's own plans, to one's own projects. What occurs at Sinai demonstrates all the foolishness and the illusory vanity of this demand since, as Psalm 106 ironically affirms, "they exchanged the glory of God for the image of an ox who eats grass" (Psalm 106:20).
Therefore the Lord responds and orders Moses to go down the mountain, revealing to him what the people were doing, and ending with these words: "Now therefore let me alone, that my wrath may burn hot against them and I may consume them: but of you I will make a great nation" (Exodus 32:10). As with Abraham in regard to Sodom and Gomorrah, so also now God reveals to Moses what he intends to do, as though not wanting to act without his agreement (cf. Amos 3:7). He says: "Let me alone, that my wrath may burn hot." In reality, this "let me alone, that my wrath may burn hot" is said precisely so that Moses might intervene and ask him not to do it, thereby revealing that God's desire is always to save. As with the two cities in the time of Abraham, punishment and destruction, in which the wrath of God is expressed as the rejection of evil, point to the gravity of the sin committed; at the same time, the intercessor's request is meant to manifest the Lord's will to forgive. This is the salvation of God, which involves mercy but together with it also exposes the truth of the sin, of the evil that is present, so that the sinner, aware of and rejecting his own sin, can allow himself to be forgiven and transformed by God. Intercessory prayer makes divine mercy so active within the corrupted reality of the sinful man, that it finds a voice in the supplication of one who prays and through him becomes present where salvation is needed.
Moses' prayer is wholly centered on the Lord's fidelity and grace. He at first relates the history of the redemption that God initiated with Israel's departure from Egypt, in order then to recall the ancient promise given to the Fathers. The Lord wrought salvation by freeing his people from Egyptian slavery; why then -- Moses asks -- "should the Egyptians say: 'With evil intent did he bring them forth, to slay them in the mountains, and to consume them from the face of the earth?'" (Exodus 32:12). The work of salvation begun must be brought to completion; if God were to allow his people to perish, this could be interpreted as a sign of a divine inability to bring to completion the project of salvation. God cannot permit this: He is the good Lord who saves, the guarantor of life, he is the God of mercy and forgiveness, of liberation from sin which kills. And so Moses appeals to God, to the interior life of God, against the exterior pronouncement. But then, Moses argues with the Lord, if his elect were to perish, even if they are guilty, he might appear incapable of conquering sin. And this is unacceptable. Moses had a concrete experience of the God of salvation; he was sent as a mediator of divine liberation, and now, with his prayer, he voices a twofold concern -- concern for the fate of his people, but alongside this, concern for the honor that is owed to the Lord, for the truth of his name. The intercessor, in fact, wants the people of Israel to be saved, because they are the flock that has been entrusted to him, but also because, in that salvation, the true reality of God is manifested. Love of the brothers and love of God interpenetrate in intercessory prayer; they are inseparable. Moses, the intercessor, is a man stretched between two loves, which in prayer overlap into but one desire for good.
Moses then appeals to God's faithfulness, reminding him of his promises: "Remember Abraham, Isaac and Israel, thy servants, to whom thou didst swear by thine own self, and didst say to them, 'I will multiply your descendants as the stars of heaven, and all this land that I have promised I will give to your descendants, and they shall inherit it forever'" (Exodus 32:13). Moses recalls the founding history of [Israel's] origins, of the fathers of the people, and of their wholly gratuitous election in which God alone had had the initiative. Not by reason of their merits did they receive the promise, but through the free choice of God and of his love (cf. Deuteronomy 10:15). And now, Moses asks that the Lord faithfully continue his history of election and salvation, by forgiving his people.
The intercessor does not make excuses for the sin of his people; he does not list presumed merits either of his people or of himself; rather, he appeals to the gratuitousness of God: a free God, who is total love, who never ceases to go in search of the one who has strayed, who always remains faithful to himself and offers the sinner the possibility of returning to him and of becoming, through forgiveness, just and capable of fidelity. Moses asks God to show himself stronger than sin and death, and by his prayer he brings about this divine self-revelation. A mediator of life, the intercessor shows solidarity with the people; desiring only the salvation that God himself desires, he renounces the prospect of becoming a new people pleasing to the Lord. The phrase that God had addressed to him, "but of you I will make a great nation," is not even taken into consideration by the "friend" of God, who instead is ready to take upon himself not only the guilt of his people, but also all of its consequences.
When, after the destruction of the golden calf, he will return to the mountain once again to ask for Israel's salvation, he will say to the Lord: "But now, if thou wilt forgive their sin -- and if not, blot me, I pray thee, out of thy book which thou hast written" (verse. 32). Through prayer, desiring God's desire, the intercessor enters ever more profoundly into the knowledge of the Lord and of his mercy, and becomes capable of a love that reaches even to the total gift of self.
In Moses, who stands upon the mountain height face to face with God, who becomes the intercessor for his people, and who offers himself -- "blot me out" -- the Fathers of the Church saw a prefiguration of Christ, who on the heights of the cross truly stands before God, not only as a friend but as Son. And not only does he offer himself -- "blot me out" -- but with his pierced heart he is blotted out, he becomes, as St. Paul himself says, sin; he takes our sins upon himself in order to spare us; his intercession is not only solidarity, but identification with us; he carries us all in his body. And in this way his whole existence as man and as Son is a cry to the heart of God, it is forgiveness, but a forgiveness that transforms and renews.
I think we should meditate upon this reality. Christ stands before the face of God and prays for me. His prayer on the cross is contemporaneous with all men, contemporaneous with me: He prays for me, he suffered and suffers for me, he identified himself with me by taking on our human body and soul. And he invites us to enter into his identity, making ourselves one body, one spirit with him, because from the heights of the cross he brought not new laws, tablets of stone, but rather he brought himself, his body and his blood, as the new covenant. He thereby makes us one blood with him, one body with him, identified with him. He invites us to enter into this identification, to be united with him in our desire to be one body, one spirit with him. Let us pray to the Lord that this identification may transform us, may renew us, since forgiveness is renewal -- it is transformation.
I would like to conclude this catechesis with the words of the Apostle Paul to the Christians in Rome: "Who shall bring any charge against God's elect? It is God who justifies; who is to condemn? Is it Christ Jesus, who died, yes, who was raised from the dead, who is at the right hand of God, who indeed intercedes for us? Who shall separate us from the love of Christ? [ … ] neither death nor life, nor angels, nor principalities [ … ] nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord" (Romans 8:33-35, 38, 39).