אָ֤ז יִמָּלֵ֪א שְׂח֡וֹק פִּינוּ֮ וּלְשׁוֹנֵ֪נוּ רִ֫נָּ֥ה אָ֭ז יֹאמְר֣וּ בַגּוֹיִ֑ם הִגְדִּ֥יל יְ֝הוָ֗ה לַעֲשׂ֥וֹת עִם־אֵֽלֶּה׃
Pada waktu itu mulut kami dipenuhi tawa, dan lidah kami dengan sorak-sorai. Pada waktu itu orang berkata di antara bangsa-bangsa: “Yang Mahakekal telah melakukan perkara-perkara besar bagi mereka ini.”
Or HaChaim
והיה כי תבא, "It will be when you come, etc." The Torah introduces this paragraph with the word והיה, indicating a joyous event; the message is that the only true reason for being joyful is when one is privileged to live in the Holy Land. Compare what David had to say about the return to Zion, i.e. (Psalms 126,2) "then our mouths will be filled with laughter."
Rabbeinu Bahya
The Mechilta also mentions that the word אז is sometimes used in the future tense and sometimes in the past tense. Examples of the word occurring in the past tense are Genesis 4,26, Exodus 4,26, Numbers 21,17, Joshua 10,12 and others. At the same time there are numerous examples of the word אז referring to future events such as in Isaiah 60,5 אז תראי ונהרת, Isaiah 58,8 אז יבקע כשחר אורך, Isaiah 35,6 אז ידלג כאיל and many others. Moses reasoned that since he had used the word אזwhen he had criticised G’d’s apparent indifference to Pharaoh’s additional decrees worsening the condition of the Jewish slaves (Exodus 4,10), it was now up to him to make amends by using the same word in exalting Him. The word אז, i.e. 1+7, is an allusion to the Unique One who reigns supreme above the seven heavens.
According to a Midrash Tanchuma on Genesis 4,26 the Israelites reasoned that seeing that word had been used when G’d punished mankind for the first time collectively when He caused one third of the dry land mass to be inundated in response to the idolatry introduced by the generation of Enosh, it was appropriate to use the same word at a time when G’d’s sovereignty on earth had been demonstrated by means of the water which had been made to retreat even from its own habitat.
The words משה ובני ישראל לאמור, teach that Moses and the Children of Israel had the good fortune to personally use this formula of exalting G’d, i.e. praising the attribute called זאת לה'. This was like the bride who applauds her husband the King and says: שיר השירים אשר לשלמה. [This mystical approach is based on the apparent redundancy otherwise of the extra words את השירה הזאת. Ed.] The author promises to deal with this in greater detail in Numbers 21,19.
According to a Midrash Tanchuma on Genesis 4,26 the Israelites reasoned that seeing that word had been used when G’d punished mankind for the first time collectively when He caused one third of the dry land mass to be inundated in response to the idolatry introduced by the generation of Enosh, it was appropriate to use the same word at a time when G’d’s sovereignty on earth had been demonstrated by means of the water which had been made to retreat even from its own habitat.
The words משה ובני ישראל לאמור, teach that Moses and the Children of Israel had the good fortune to personally use this formula of exalting G’d, i.e. praising the attribute called זאת לה'. This was like the bride who applauds her husband the King and says: שיר השירים אשר לשלמה. [This mystical approach is based on the apparent redundancy otherwise of the extra words את השירה הזאת. Ed.] The author promises to deal with this in greater detail in Numbers 21,19.
Rashi
And a time to laugh. In the time to come, as it is stated, “Then our mouth will be filled with laughter.”7Tehillim 126:2.