It’s the conclusion of Gaudium et Spes Part 1, Chapter 1. It wraps up a long look at the dialogue with atheism with a brief treatise on christology, beginning with a basic Christian stance:
The truth is that only in the mystery of the incarnate Word does the mystery of (humankind) take on light. For Adam, the first (human being), was a figure of Him Who was to come,(cf. Rom. 5: 14. cf. Tertullian, De carnis resurrectione 6: “The shape that the slime of the earth was given was intended with a view to Christ, the future man.”): namely Christ the Lord. Christ, the final Adam, by the revelation of the mystery of the Father and His love, fully reveals (humankind) to (humankind itself) and makes (their) supreme calling clear. It is not surprising, then, that in Him all the aforementioned truths find their root and attain their crown.
Christ is source of all truth; the “author of life,” if you will. The language is strong, but it does not include a reverse statement, namely, those persons or philosophies that embrace “darkness” or what does not result in “roots or crown.”
The human being, biological, psychological, and spiritual, is honored because of Christ’s participation in human work, human thought, and human love:
He Who is “the image of the invisible God” (Col. 1:15),(cf. 2 Cor. 4:4) is Himself the perfect (human being). To the (children) of Adam He restores the divine likeness which had been disfigured from the first sin onward. Since human nature as He assumed it was not annulled,(cf. Second Council of Constantinople, canon 7: “The divine Word was not changed into a human nature, nor was a human nature absorbed by the Word.” Denzinger 219 (428); cf. also Third Council of Constantinople: “For just as His most holy and immaculate human nature, though deified, was not destroyed (theotheisa ouk anerethe), but rather remained in its proper state and mode of being”: Denzinger 291 (556); Cf. Council of Chalce, don:” to be acknowledged in two natures, without confusion change, division, or separation.” Denzinger 148 (302)) by that very fact it has been raised up to a divine dignity in our respect too. For by His incarnation the Son of God has united Himself in some fashion with every (person). He worked with human hands, He thought with a human mind, acted by human choice(cf. Third Council of Constantinople: “and so His human will, though deified, is not destroyed”: Denzinger 291 (556)) and loved with a human heart. Born of the Virgin Mary, He has truly been made one of us, like us in all things except sin.(cf. Heb. 4:15)
The “way of the cross” is one for imitation and for following:
As an innocent lamb He merited for us life by the free shedding of His own blood. In Him God reconciled us(cf. 2 Cor. 5:18-19; Col. 1:20-22) to Himself and among ourselves; from bondage to the devil and sin. He delivered us, so that each one of us can say with the Apostle: The Son of God “loved me and gave Himself up for me” (Gal. 2:20). By suffering for us He not only provided us with an example for our imitation,(cf. 1 Pet. 2:21; Matt. 16:24; Luke 14:27) He blazed a trail, and if we follow it, life and death are made holy and take on a new meaning.
The assumption is that Christians willingly and enthusiastically imitate Christ, thus coming to a deeper realization of the Paschal Mystery:
The Christian (person), conformed to the likeness of that Son Who is the firstborn of many brothers (and sisters),(cf. Rom. 8:29; Col. 3:10-14) received “the first-fruits of the Spirit” (Rom. 8:23) by which he (or she) becomes capable of discharging the new law of love.(cf. Rom. 8:1-11) Through this Spirit, who is “the pledge of our inheritance” (Eph. 1:14), the whole (person) is renewed from within, even to the achievement of “the redemption of the body” (Rom. 8:23): “If the Spirit of him who raised Jesus from the death dwells in you, then he who raised Jesus Christ from the dead will also bring to life your mortal bodies because of his Spirit who dwells in you” (Rom. 8:11).(cf. 2 Cor. 4:14) Pressing upon the Christian to be sure, are the need and the duty to battle against evil through manifold tribulations and even to suffer death. But, linked with the paschal mystery and patterned on the dying Christ, (she or) he will hasten forward to resurrection in the strength which comes from hope.(cf. Phil. 3:19; Rom. 8:17)
Romans 8:32 is pretty clear, pro multis aside. Christ’s death was an unconditional offering for the entire human race. Note the wording below: “we ought.” The Church suggests we ought to approach the question of salvation with confidence, even if we can’t see a logical path for the Holy Spirit to work.
All this holds true not only for Christians, but for all (people) of good will in whose hearts grace works in an unseen way.(cf. Second Vatican Council, Dogmatic Constitution on the Church, Chapter 2, n. 16: AAS 57 (1965), p. 20) For, since Christ died for all men,(cf. Rom. 8:32) and since the ultimate vocation of (the human person) is in fact one, and divine, we ought to believe that the Holy Spirit in a manner known only to God offers to every (person) the possibility of being associated with this paschal mystery.
And a fine conclusion:
Such is the mystery of (humankind), and it is a great one, as seen by believers in the light of Christian revelation. Through Christ and in Christ, the riddles of sorrow and death grow meaningful. Apart from His Gospel, they overwhelm us. Christ has risen, destroying death by His death; He has lavished life upon us(cf. The Byzantine Easter Liturgy) so that, as (daughters and) sons in the Son, we can cry out in the Spirit; Abba, Father(cf. Rom. 8:15 and Gal. 4:6; cf. also John 1:22 and John 3:1-2)
The suggestion is that non-Christians are liable to an overwhelming experience. If so, the Christian approach is one of charity and comfort, not condemnation.