When the wise men from the East failed to return to Jerusalem from Bethlehem to tell Herod about the new-born king, but, at the angel’s command, returned to their home another way, Herod was as furious as a wild beast, and commanded that all the children of two years and under in Bethlehem and its surroundings be killed. This terrible command of the king's was carried out to the letter. His soldiers cut off some of the children's heads with their swords, dashed others on the stones, trampled some of them underfoot and drowned others with their own hands. The weeping and lamentation of their mothers rose to heaven: ‘Lamentation and bitter weeping, Rachel weeping for her children’ as had been prophesied (Jer. 13:15; Matt. 2:18). This evildoing towards the hordes of innocent children came to pass a year after the birth of Christ, at a time when Herod was trying to find the divine Child. He sought Zacharias’s son, John, meaning to kill him in the belief that John was the new king. When Zacharias refused to hand John over, he was killed in the Temple on Herod’s orders. St Simeon the Host of God was also killed, and went to God soon after the Presentation in the Temple. Slaying the children in Bethlehem, Herod then turned on the Jewish elders, who had revealed to him where the Messiah would be born. He killed Hyrcanes the High Priest, and seventy elders from the Sanhedrin, and thus they who conspired with Herod to kill the new baby King came to an evil end. After that, Herod killed his own brother and sister and wife, and three of his sons. Finally, God’s punishment fell on him: he began to tremble, his legs swelled, the lower part of his body became putrid and worms came out of the sores, his nose became blocked and an unbearable stench spread around from it. At the time of his death, he remembered that there were many captive Jews in prison, so, that they should not rejoice at his death, he ordered that they all be slaughtered. Thus this terrible ruler lost his inhuman soul and was given to the devil for eternity. 
As Gordon Giles writes in his comments on the haunting Christmastide song of the Holy Innocents known as the ‘Coventry Carol’:
We live in a violent, cruel world in which human beings damage, maim, and kill one another with calculated spite or mindless violence. This is our world, and it is God's world. It is the same world into which God himself was born, and is only different today because Christ took human flesh and made a difference. 
I discussed the Massacre of the Innocents in some detail in last year’s post for today. I have little to add to that post, but Brigit at Under the Oak has some wonderful things in her post for this feast. First, she gives the Martyrology of Oengus for the feast (celebrated on 28 December in the West):
28. Famous is their eternal acclamation,
beyond every loveable band,
which the little children from Bethlehem
sing above to their Father.
Then, following the comments of a scholiast, Brigit posts two stanzas of Blathmac, and finishes with this ‘Mothers’ Lament at the Slaughter of the Innocents’ from the Leabhar Breac:
Then, as she plucked her son from her
breast for the executioner, one of the
‘Why do you tear from me my darling son,
The fruit of my womb?
It was I who bore him, he drank my breast.
My womb carried him about, he sucked my vitals.
He filled my heart:
He was my life, ’tis death to have him taken from me.
My strength has ebbed,
My voice is stopped,
My eyes are blinded.’
Then another woman said:
‘It is my son you take from me.
I did not do the evil,
But kill me—me: don’t kill my son!
My breasts are sapless, my eyes are wet,
My hands shake,
My poor body totters.
My husband has no son,
And I no strength;
My life is worth—death.
Oh, my one son, my God!
His foster-father has lost his hire.
My birthless sicknesses with no requital until Doom.
My breasts are silent,
My heart is wrung.’
Then said another woman:
‘Ye are seeking to kill one; ye are killing many.
Infants ye slay, fathers ye wound; you kill the mothers.
Hell with your deed is full, heaven shut.
Ye have spilt the blood of guiltless innocents.’
And yet another woman said:
‘O Christ, come to me!
With my son take my soul quickly:
O Great Mary, Mother of the Son of God,
What shall I do without my son?
For Thy Son, my spirit and my sense are killed.
I am become a crazy woman for my son.
After the piteous slaughter
My heart’s a clot of blood
From this day
Till Doom comes.’
In conclusion, here is the Kontakion of the Holy Infants:
When the King was born in Bethlehem, the Magi arrived from the East with gifts guided by a Star on high, but Herod was troubled and mowed down the children like wheat; for he lamented that his power would soon be destroyed. 
May the ruthless slaughter of children come to an end soon.
 St Nicholas (Velimirović), The Prologue from Ochrid, Vol. 4, trans. Mother Maria (Birmingham: Lazarica, 1986), p. 384.
 The Great Horologion, trans. HTM (Boston: HTM, 1997), p. 363.