CCC 467 The Monophysites affirmed that the human nature had ceased to exist as such in Christ when the divine person of God’s Son assumed it. Faced with this heresy, the fourth ecumenical council, at Chalcedon in 451, confessed:
Following the holy Fathers, we unanimously teach and confess one and the same Son, our Lord Jesus Christ: the same perfect in divinity and perfect in humanity, the same truly God and truly man, composed of rational soul and body; consubstantial with the Father as to his divinity and consubstantial with us as to his humanity; “like us in all things but sin”. He was begotten from the Father before all ages as to his divinity and in these last days, for us and for our salvation, was born as to his humanity of the virgin Mary, the Mother of God.¹
We confess that one and the same Christ, Lord, and only-begotten Son, is to be acknowledged in two natures without confusion, change, division or separation. The distinction between the natures was never abolished by their union, but rather the character proper to each of the two natures was preserved as they came together in one person (prosopon) and one hypostasis.²

CCC 540 Jesus’ temptation reveals the way in which the Son of God is Messiah, contrary to the way Satan proposes to him and the way men wish to attribute to him.³ This is why Christ vanquished the Tempter for us: “For we have not a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tested as we are, yet without sinning.”⁴ By the solemn forty days of Lent the Church unites herself each year to the mystery of Jesus in the desert.

CCC 609 By embracing in his human heart the Father’s love for men, Jesus “loved them to the end”, for “greater love has no man than this, that a man lay down his life for his friends.”⁵ In suffering and death his humanity became the free and perfect instrument of his divine love which desires the salvation of men.⁶ Indeed, out of love for his Father and for men, whom the Father wants to save, Jesus freely accepted his Passion and death: “No one takes [my life] from me, but I lay it down of my own accord.”⁷ Hence the sovereign freedom of God’s Son as he went out to his death.⁸

CCC 612 The cup of the New Covenant, which Jesus anticipated when he offered himself at the Last Supper, is afterwards accepted by him from his Father’s hands in his agony in the garden at Gethsemani,⁹ making himself “obedient unto death”. Jesus prays: “My Father, if it be possible, let this cup pass from me. ..”¹⁰ Thus he expresses the horror that death represented for his human nature. Like ours, his human nature is destined for eternal life; but unlike ours, it is perfectly exempt from sin, the cause of death.¹¹ Above all, his human nature has been assumed by the divine person of the “Author of life”, the “Living One”.¹² By accepting in his human will that the Father’s will be done, he accepts his death as redemptive, for “he himself bore our sins in his body on the tree.”¹³

CCC 1137 The book of Revelation of St. John, read in the Church’s liturgy, first reveals to us, “A throne stood in heaven, with one seated on the throne”: “the Lord God.”¹⁴ It then shows the Lamb, “standing, as though it had been slain”: Christ crucified and risen, the one high priest of the true sanctuary, the same one “who offers and is offered, who gives and is given.”¹⁵ Finally it presents “the river of the water of life. .. flowing from the throne of God and of the Lamb,” one of most beautiful symbols of the Holy Spirit.¹⁶

CCC 2602 Jesus often draws apart to pray in solitude, on a mountain, preferably at night.¹⁷ He includes all men in his prayer, for he has taken on humanity in his incarnation, and he offers them to the Father when he offers himself. Jesus, the Word who has become flesh, shares by his human prayer in all that “his brethren” experience; he sympathizes with their weaknesses in order to free them.¹⁸ It was for this that the Father sent him. His words and works are the visible manifestation of his prayer in secret.

CCC 2778 This power of the Spirit who introduces us to the Lord’s Prayer is expressed in the liturgies of East and of West by the beautiful, characteristically Christian expression: parrhesia, straightforward simplicity, filial trust, joyous assurance, humble boldness, the certainty of being loved.¹⁹

1 Council of Chalcedon (451): DS 301; cf. Heb 4:15.
2 Council of Chalcedon: DS 302.
3 Cf Mt 16:2 1-23.
4 Heb 4:15.
5 Jn 13:1; 15:13.
6 Cf. Heb 2:10,17-18; 4:15; 5:7-9.
7 Jn 10:18.
8 Cf. Jn 18:4-6; Mt 26:53.
9 Cf. Mt 26:42; Lk 22:20.
10 Phil 2:8; Mt 26:39; cf. Heb 5:7-8.
11 Cf. Rom 5:12; Heb 4:15.
12 Cf. Acts 3:15; Rev 1:17; Jn 1:4; 5:26.
13 1 Pt 224; cf. Mt 26:42.
14 Rev 4:2, 8; Isa 6:1; cf. Ezek 1:26-28.
15 Rev 5:6; Liturgy of St. John Chrysostom, Anaphora; cf. Jn 1:29; Heb 4:14-15; 10:19-2.
16 Rev 22:1; cf. 21:6; Jn 4:10-14.
17 Cf. Mk 1:35; 6:46; Lk 5:16.
18 Cf. Heb 2:12, 15; 4:15.
19 Cf. Eph 3:12; Heb 3:6; 4:16; 10:19; 1 Jn 2:28; 3:21; 5:14.