Plain text of Barnabas VIII
1 But what do you think that it typifies, that the commandment has been given to Israel that the men in whom sin is complete offer a heifer [to GOD], and slay it and burn it, and that boys then take the ashes and put them into vessels and bind scarlet wool on sticks and hyssop, and that the boys all sprinkle the people thus one by one in order that they all be purified [by repentance] from their sins?
4 But why are there three boys who sprinkle? As a testimony to Abraham, Isaac, and Jacob, for these are great before GOD.
7 And for this reason the things which were thus done are plain to us, but obscure to them, because they did not hear the Lord’s voice.