Here are some quotes from Origen on infant baptism, including the quote I used in my last post about Origen:
1. In his Homilies on Luke (XIV on 2:22a) he remarks “therefore children also are baptized”.
2. In his Homilies on Leviticus (VIII 3 on 12.2) he says baptism is given “according to custom of the Church, to infants also”.
3. Most famous of all, in his Commentary on Romans (V 9 on 6:5-7) he states “For this reason, moreover, the Church received from the apostles the tradition of baptizing infants too”.
Joachim Jeremias notes, “The passages quoted were written between 233 and 251, but they take us back to a considerably earlier period. For Origen maintains – as Hippolytus, shortly before and independently of him, had done in Rome – that infant baptism was a custom reaching back to apostolic times. He could hardly have expressed himself thus if he had not himself been baptized as a paidion (Origen was born in 185 in Egypt). When we note that his family, as Eusebius credibly informs us, had been Christian for several generations, we must add that he could hardly have spoken of a ‘tradition handed down from the apostles’ had he not known that at least his father and probably also his grandfather had been baptized as paidia. This means that the tradition of his family carries us back from that date of his own baptism at least to the date of his father’s – i.e. to the middle of the second century, and probably even to the baptism of his grandfather in the first half of that century.”
– quoted from Infant Baptism in the First Four Centuries, pp. 65-66.
spes clara 