The following extract is taken from Abortion and Martyrdom edited by Aidan Nichols, O.P.
God the Father sees all children in his Son, his Son in all children, but the Innocents of Bethlehem resemble the Only-Begotten in a unique way, for they are his contemporaries and compatriots, as well as his comrades in the infant state of his human nature:
The Holy Innocents of Bethlehem are united with the Son, and confess his Incarnation, simply by the fact of their infancy and the time and place of their birth, and through this bond they are sanctified by the Holy Spirit, dying a death that is true martyrdom, a Baptism in blood that confers the salvific effects of Baptism in water. This is the doctrine of Pope St Leo the Great, preaching on the Solemnity of the Epiphany:
Quoting Prudentius's hymn sung by the Church on their feast day, Péguy shows how the Holy Innocents reveal the true character of Paradise. It is a playground. The Holy Innocents romp in the nurseries of Heaven, in the nursery of God's sons, which is what Heaven is:
For Prudentius and Péguy, as also for Dante, the merriment of 'unpretentious' Paradise, the blissful act of beholding the Trinity, is a kind of play.  Spiritual childhood is not only the way to Heaven, it is Heaven's very life.
The battle which Péguy fought for innocence and the Innocents still rages. It is the central struggle of our century, compared with which the clash of nations and ideologies are trifling skirmishes. Péguy's call to arms, issued in the spirit of Christian chivalry, defines both the end and the means of the fight. The end is the glory of the Triune God and the defence of the least of Christ's brethren, and the means are the virtues of the Little Way, a childlike exercise of faith, hope, and charity (accompanied, as we have seen, by a manly exercise of the moral virtues). To defend the Innocents we must strive, by God's grace, to be like them. By artless fidelity to the truth in a world of adult deceit, by a humble confidence that disarms the giants of despair, by a prodigal love of the smallest of our brethren, we follow the Lamb wherever he goes. Our simplicity will be our strength.  This is the true 'mystery of the charity of Joan of Arc', France's boldest warrior and youngest saint, and it is the final paradox of Péguy's Christian theology of childhood: only the Lamb-like learn the secret of the Lion.
This is only a speculation. However, there seems to be some support for at least some elements
of the argument in Pope John Paul II's encyclical Evangelium Vitae. There the Holy Father says that the Child whom the Dragon seeks to devour in the vision of St John (cf.
Rev. 12:4) is 'a figure of Christ' and at the
same time 'a figure of every person, every child, especially every helpless
baby whose life is threatened, because, as the Council reminds us, 'by his Incarnation the Son of God has united
Himself in some fashion with every man'. It is precisely in the 'flesh' of every man that Christ continues to reveal himself and to enter
into fellowship with us, so that rejection of human life, in whatever form that rejection
takes, is really a rejection of Christ. This is the fascinating but also demanding
truth which Christ reveals to us, and which his Church continues untiringly to proclaim: 'Whoever receives one such child in my name receives me' (Matt 18:5); 'Truly, I say to you, as you did it to one of the least of these my brethren, you did it
to me' (Matt. 25:40) 
2. Ibid. p. 819.
3. In Epiphaniae solemnitate sermo 2, n. 3; Sources Chrétiennes 22B, p. 224.
4. 'Le mystère des saints innocents', op. cit., p. 823.
5. '...l'ultimo è tutto d'Angelici ludi' (Dante, Paradiso, Canto 28, 126).
6. Preaching on the feast of St Stephen, St Bonaventure says: 'Grace
7. 'Le mystère des saints innocents', op. cit., p. 806f.
8. Evangelium Vitae, n. 104. The passage in italics is partly italicized in the original text.
* The Editor and publishers are grateful for permission granted by T. & T.
Clark to re-print this section of J. Saward, The Way of the Lamb. The
Spirit of Childhood and the End of theAge (Edinburgh: T. & T.
Version: 7th February 2003