Mat 23:38 Behold, your house is left unto you desolate.
Mat 23:39 For I say to you, You shall not see me henceforth, till ye shall say, Blessed [is] he that comes in the name of the Lord.
Alternative: See, your house has left you empty. I tell you that you will not know me from now until you speak to praise the one who comes in Lord's name.

This ends this chapter, which focuses on attacking what Christ considered the selfish interests of the church leaders of his time. Its verses are so complexly woven together that it makes me want to go back to other long dissertations by Christ and see if their ideas were woven together so tightly. "Woven" is exactly the right term because threads of ideas are seemingly dropped only to be referred to in later verses.

The first verse seems to simply follow up on the previous two verse where Christ predicts the destruction of his generation of Jews, but the reference to the Jews as a "house" ties it to verse Mat 23:14, where Christ attacks the religious leaders for "devouring widows' houses," and to Mat 23:29, where the term "build" referring to the tombs of the prophets is in Greek really "house building" with the same Greek roots as "house" (oikos). So this reference to the desolate house of Israel is tied clearly to widows' houses being devoured by the Jewish religious leaders, and the tombs that they have built to the Prophets. It reads like prose in English, but upon closer inspection in Greek it is practically poetry. Christ weaves together all these ideas to reinforce his message.

In the second verse, the woven word is the second "say," (epo) which refers to Mat 23:3 where the same word is translated as "bid," referring to the religious authorities telling people what they should do. It is different than the "say" (lego) that Christ uses to describe his talking to people. Christ seems to use the former for much more formal pronouncements. Christ uses this term (epo) when he refuses to tell these same religious leader by what authority he teaches people (Mat 21:27).

The idea is that these religious leaders cannot understand Christ until they change their tune. Right now, their official pronouncements are all about telling others what to do. They cannot understand God until they start praising those who come in the name of the Lord instead of condemning them to death.

It may also be important to note the word translated as "blessed" is not the word from the Beatitudes, which has the sense of being fortunate. Instead it means to praise or honor someone.

"Left " is from aphiêmi, which means "to let fall," "to send away," "to let loose," "to get rid of," "to leave alone," "to pass by," "to permit," and "to send forth from oneself." This is the same word that is translated as "leave" and "forgive" in the New Testament.

"Desolate" is from erêmos, which when referring to places, means "deserted" or "empty."

The first "say" in the second verse if from legô, which means "to gather," "to pick up," "to count," "to tell," "to recount," "to say," "to speak," and "to call by name." It doesn't mean speaking, but in the sense of connecting things together, enumerating things, recounting things.

"See" is from eido, which means "to see," "to examine," and "to know."

The second "say" is from the word epo, which means "to speak" or "to say" (from epos, which means "word').

"Blessed" is from eulogeô, which means "to speak well of," "to praise," "to bless," by Hebrew euphemism, "to curse."