The Rebbe says that the famous teaching of Reb Levi Yitzchok of Berdichev, that on this Shabbos, Shabbos Chazoin, we are shown a image of the third Holy Temple – so why was this teaching revealed only recently, even though it was going on for thousands of years – the nature of sadness which is loss, is, because like a teacher who is speaking to his pupil but suddenly gets a deeper idea, and wishes to understand the idea fully in order to teach it… – so for a moment he withdraws into his own self – similarly, for God to bring about the infinite redemption, the unity of God and man – it was a state of withdrawal