Origen

“ Every one that gives his adherence to Jesus as the Son of God according to the true history concerning Him, and by deeds done according to the Gospel, is on the way to living the life which is according to virtue, is converted and is on the way towards becoming as the little children ”

“ But it is a hard task to expound what follows in logical harmony with what has already been said; for one might say, how is it that he who is converted and has become as the little children, is a little one among such as believe in Jesus, and is capable of being caused to stumble? ”

“ But when they cause to stumble one of the little ones pointed out by Jesus, who are believers in Him, he shall assume an ass’s millstone, the corruptible body which presses heavily on the soul, which is itself hung from the neck, which is dragged down to the affairs in this life, that by means of these their conceit may be taken away, and having paid the penalty, they shall come, through means of the ass’s millstone, to the condition expedient for them. ”