your... you. Very emphatic. At the beginning of the Lord's ministry it was "My Father's house" (John 2:16); but at the end, after His rejection, it was "your house".
house: i.e. the Temple, where He was speaking.
is left. is being left. See Matthew 24:1.
desolate. Every "house" and every place is "desolate" where Christ is not.