The quote is by Guerric of Igny, Liturgical sermons, vol. 2, translated by ‘Monks of Mount Saint Bernard, CF 32, 1971, page 81.
“What I have placed before you brethren, is like an egg or a nut; break the shell and you will find the food. Beneath the image of Joseph you will find the Paschal Lamb, Jesus, the one for whom you yearn. The great depth at which he is hidden and the diligence necessary in seeking him and the difficulty you will have in finding him will only make him sweeter to your taste. . . . And so here is the explanation in a nutshell: If we think with faith and reverence about the meaning of his name (Gen 30:24 : Joseph=”May He Add”; sounds like Heb. ”He has taken away” – my comment). . . . That after he had been sold by his own he redeemed his own from death, that he was humbled even to imprisonment, then elevated to a throne, and was rewarded for his work by being given a new name among the nations (Gen 41:45) – ‘The Saviour of the World’ – if we think about all these things reverently and faithfully, we shall surely recognize how truly it was said by the Lord (Hos 12:10), “Through the prophets, I gave parables.”