>>613079 (OP)
This comes from "The Orthodox Study Bible" page 1269 Matthew 2:16-18.
>16 Then Herod, when he saw that he was mocked of the wise men, was exceeding wroth, and sent forth, and slew all the children that were in Bethlehem, and in all the coasts thereof, from two years old and under, according to the time which he had diligently inquired of the wise men.
>17 Then was fulfilled that which was spoken by Jeremiah the prophet, saying,
>18 In Rama was there a voice heard, lamentation, and weeping, and great mourning, Rachel weeping for her children, and would not be comforted, because they are not.
"These slaughtered children are regarded as saints and martyrs in the Church and are known as the Holy Innocents."
These children, some of whom were old enough to have done at least a few bad things (although probably not sinful things, as I doubt any of them freely chose to rebel against the loving purpose of God), weren't baptised and hadn't professed their belief in Christ, but they are still regarded by the Orthodox Church to be in Heaven.