When the Holy Temple was destroyed, there was a wailing voice heard throughout the whole world. The Ministering Angels said to G-d, "Master of the Universe, do You have such emotions of sadness? Isn't it written 'Splendor and glory are before You?' "
G-d answered: "My House is destroyed, and My children are manacled in chains. Shouldn't I be suffering?"
- Midrash, Yalkut Shimoni, Tehillim 679
From the day that Jerusalem and the Holy Temple were destroyed, there is no joy before G-d... until Jerusalem will be rebuilt and the Jewish People will return to it.
- Midrash, Yalkut Shimoni, Eychah 7009
It is precisely at times of closeness - i.e. prayer - that G-d feels the most suffering over the destruction of the Holy Temple.)
Rebbe Yosie said, "I was once traveling on the road, and I entered into one of the ruins of Jerusalem in order to pray. Elijah the Prophet appeared and waited for me at the door until I finished my prayer.
"My son, what sound did you hear in this ruin?" he asked.
I replied, "I heard a divine voice, cooing like a dove and saying: 'Woe to the children, on account of whose sins I destroyed My House, burnt My Temple, and exiled them among the nations of the world.'"
Elijah said to me, "Not only at this moment does G-d say this, but He exclaims it three times a day."
- Talmud, Brachot 3a