וְהָיָ֕ה כִּֽי־יֹאמְר֥וּ אֲלֵיכֶ֖ם בְּנֵיכֶ֑ם מָ֛ה הָעֲבֹדָ֥ה הַזֹּ֖את לָכֶֽם׃
And it shall come to pass, when your children shall say unto you: What mean ye by this service?
Targum Jonathan on Exodus
And it shall be that when at that time your children shall say to you, What is this your service?