אָז֩ תִּרְצֶ֨ה הָאָ֜רֶץ אֶת־שַׁבְּתֹתֶ֗יהָ כֹּ֚ל יְמֵ֣י הֳשַׁמָּ֔ה וְאַתֶּ֖ם בְּאֶ֣רֶץ אֹיְבֵיכֶ֑ם אָ֚ז תִּשְׁבַּ֣ת הָאָ֔רֶץ וְהִרְצָ֖ת אֶת־שַׁבְּתֹתֶֽיהָ׃
Wtedy uczyni zadość ziemia Sabbatom swoim po wszystkie dni opustoszenia swego, gdy będziecie w ziemi wrogów waszych; wtedy odpocznie ziemia i zaspokoi Sabbaty swoje.
Tiferet Shlomo
It seems correct to explain the meaning of this verse: the intent of the verse is to highlight the great virtue of Shabbos during galut: when Shabbos comes, it brings more simcha to G-d than when the Beis HaMikdash stood. [Why?] Because on Shabbat there's a yichud in heaven, even during galut, and during the days of the week, Hashem is in "exile" as it says "I am with him in his pain." So, when Shabbat comes, there's a great joy because Hashem leaves the exile and there's a yichud. In the times of Beit HaMikdash, there was a yichud during the week and on Shabbat it was on a higher level, but, as a result, it wasn't as joyous to Hashem. This is the meaning of the verse "then during the times of the exile the earth will desires its Sabbatical": they are desirable to Hashem with great joy. It says in the verse "It's enough for you to stay by this mountain," [which, homiletically, praises Shabbat]: your Shabbat is very great for you in the time of great tears. Now, the days of the three weeks are a time of deep tears-- as a result, this Shabbat is even greater than all other Shabbotim because during the week there is great pain, but, during Shabbat, it's great joy as it says "on the 7th day He ascended and sat on His throne of glory" and, even though the Jewish people are pain, there's no pain for Hashem on Shabbat. What we learn from this is that every single Jew must be very joyous on Shabbat; the main pain [that Jews] should experience is that the shechina is galut (during the weekday), but on Shabbat the shechina is in peace, so th Jewish people should be joyous, and this causes more simcha to Hashem.